SPERMATAPHORES AS A Means of Hypodermic Impregnation. BY C. O. WHITMAN. Reprinted from the Journal of Morphology, V IV., No. 3. V / • " : BOSTON: GINN & COMPANY. 1891. SPERMATAPHORES AS A Means of Hypodermic Impregnation BY C. O. WHITMAN. Reprinted from the Journal of Morphology, Voi. IV., No. 3. BOSTON: GINN & COMPANY. 1891. SPERMATOPHORES AS A MEANS OF HYPO- DERMIC IMPREGNATION. C. O. WHITMAN. Although it is well known that spermatophores are of very- general occurrence among the invertebrates, and even among many vertebrates, the assertion that, as a perfectly regular and normal affair, in animals as highly organized as the leeches, they represent an injecting apparatus, by means of which the spermatic elements of one individual are forced through the body- wall of another, at any point whatsoever, may appear almost in- credible, even when supported by direct observation many times repeated on different species. That such is certainly the case, however, is very easily demonstrated, and any one can verify it as often as he likes on almost any species of Clepsine that hap- pens to be accessible. The observations to be presented in this paper will make this fact abundantly evident. But what becomes of these spermatic injections ? Do they ever reach the eggs and fertilize them ? and if so, is this the normal method of bringing the sexual products together ? Al- though I cannot affirm this as a positive certainty, the evidence seems to me to fall but little short of being conclusive. I have studied closely the habits of these leeches in Europe, Japan, and America, and with especial reference to settling the question of when and how impregnation is effected. Long-continued obser- vation under most favorable circumstances has never given me so much as a single indication that the genital pores are ever united in the act of copulation. On the other hand, the plant- ing of spermatophores on the surface of the body at any point that happens to come first, is a common occurrence, which one may often see repeated several times in the course of a few hours by the same individual. I have followed the track of the spermatozoa from the point of penetration to the coelomic cavity in which the ovaries lie, but I have not pursued the subject far enough to determine when or how the spermatozoa pass through the wall of the ovisacs. That spermatozoa get 3 62 WHITMAN. [Vol. IV. into the ovisacs, and that fertilization takes place before oviposi- tion, can be demonstrated by facts that admit of no doubt. The passage through the wall of the ovisac — the only link in the chain of direct evidence yet to be supplied — seems to be an inference justified by all the known facts. Such a passage, in the absence of any definite openings in the ovarian walls, would have to be a forced one, depending upon the action of the spermatozoa themselves. As these walls are represented by a thin membrane which becomes enormously distended as the eggs enlarge to maturity, the difficulty of penetration could not be great; and the case of Peripatus and the Turbellarians seems to show that spermatozoa are capable of effecting automatically such a passage. The view here taken finds a very strong confirmation in the fact that precisely the same mode of copulation occurs in many Turbellarians, in the Rotifers, and in Dinophilus, as the cita- tions from Lang, Plate, and Harmer, given farther on, fully show. The indications are that it occurs also in many oligo- chaetous annelids, as well as in several genera of leeches besides Clepsine,—perhaps in all the Rhynchobdellidae. The occur- rence of such a mode of copulation among so many of the lower bilateral animals appears not only to render explicable the pluri- penial condition of many Turbellarians and some of the higher worms, but also to clear up many puzzling observations in regard to fertilization in animals that have no intromittent organ. It is no longer necessary to suppose that the spermatophores found attached to different parts of the body of Peripatus must be carried through the vagina and up the uteri in order to reach the eggs ; and the discovery of spermatozoa projecting through the ovarian walls of this animal, as reported by Moseley and Sedgwick, ceases to be so complete a mystery. The difficulties in the way of understanding how spermatophores can be of any use when attached at a considerable distance from any genital pore, and completely closed externally, as described by Vej- dovsky for many annelids, may not be so great as they have hitherto appeared. The facts and bibliographical notes to be presented in this paper are sufficient, I think, to make it at least probable that the original function of the spermatophore was precisely what it now is in the Turbellarians, the Rotifers, Dinophilus, and No. 3.] SPERMA TO PH ORES. 363 Clepsine, — the injection of spermatozoa through the body-wall, or hypodermic impregnation, as we may call it. This mode of impregnation represents an important economi- cal step in advance of the more primitive mode of setting the seminal elements free in the water. The deposition of sperm- capsules at random on any point of the external surface that happens to be accessible at the moment of meeting, is improved upon by restricting the act to a definite region, as one or more segments of the clitellum in certain annelids, or the surface around the external openings of the oviducts, as in the crayfish ; and, still further, by limitation to the edge of genital pores or seminal receptacles, as in the copepods. The seminal reservoir of the lobster, discovered by Bumpus,1 marks an advance on the conditions obtaining in the crayfish. The habit of discharging spermatophores directly into the vaginal orifice, presupposing direct union of the sexual pores, brings us to relations where such copulatory organs as we find in the Gnathobdellidae would become useful. The penis is here only an eversible end-piece of the vasa deferentia — a simple tubular elongation of what in its simplest form would be repre- sented by a pore. Lang, who was the first to discover this mode of impregna- tion in the Turbellaria, has thrown out the interesting sugges- tion, that in these animals the penes may have been primarily organs of attack and defence, which assumed secondarily the office of copulatory organs. The grounds for the suggestion may be seen from a citation to be introduced farther on. Such a mode of origin, though it may be true for the Turbellaria, does not invalidate the suggestion I have made for the Gnathob- dellidae, except on the supposition that the penes represent homologous organs in the two groups. Such a supposition appears to be forbidden by the absence of these organs in the lower leeches. It seems to me, therefore, altogether more prob- able that in the higher leeches they have been independently acquired, and that their evolution began after, or simultaneously with, the establishment of the habit of true copulation. The structural and ontogenetic resemblances of the penes in the two groups cannot be taken as decisive proof of genetic identity. The resemblances between the penis and the pharynx 1 The Embryology of the American Lobster. Journ. Morph., Voi. V. [ In press.] 364 WHITMAN. [Vol. IV. of a Turbellarian are of the same nature and equally close ; but no one would in this case be likely to mistake such resem- blances for homologies.1 In view of the fact that the spermatophores of Clepsine were discovered nearly half a century ago by Friedrich Müller, and described as a “phacnomenon cujus ncque analogon inter reliqua ammalia reperire,” and that they have since been observed by Max Schultze, Leuckart, Leydig, and Schneider, it may appear a little remarkable that their function should have so long escaped detection. But when we consider how totally unpre- pared were the minds of investigators for such a mode of impregnation, we find no difficulty in understanding how it comes to pass that the old belief still prevails, that all the Hirudinea, penis or no penis, copulate in essentially the same manner, and fecundate by conveying the spermatic fluid of one individual (or of both reciprocally) directly into the female geni- tal orifice of the other, thus placing it where it can pass unob- structed into the so-called uterus, or, in the absence of such a specialized part, into the ovarian sacs. While this has been, and still is, the opinion generally re- ceived, the possibilities of the eggs being fertilized after deposit, of self-fertilization, and of parthenogenetic development, have not been overlooked. The following notes and extracts are designed to give the history of the subject, and to show what questions have been left unsettled. Historical Notes and Extracts relating to the Hirudinea. i. Clepsine complanata. FRIDERICUS MUELLER. De Hirudinibus circa Berolinum hucusque observatis. Berolini, 1844. pp. 33, 34. “ Cleps. complanatas, quamvis plurimas amoris tempore continua attentione observaverim, coiuntes nunquam observavi;2 sed eodem 1 We are continually reminded that parallel development has been a much more important factor in evolution than has generally been supposed. Similar bases, similar needs, similar variations (because predetermined by like causes), guided by parallel selective influences, which would be sustained by like environments, have unquestionably resulted in numberless analogies which are usually allowed to pass as evidences of genetic affinity. 2 Braun (Systematische Beschreibung einiger Egelarten, Berlin, 1805, p. 60) makes the same observatiom No. 3.] SPERMA TO PH ÖRES. 365 fere ante ovorum partum tempore, quo Cleps. tessulatae coire solent, singulare mihi in Cleps. complanatis sese obtulit phaenomenon, cujus neque analogon inter reliqua ammalia reperireneque explicationem dare valeo. Ad utrumque nimirum faciei ventralis latus organa singu- laria filiformia, tres usque quinque corporis annulos longitudine aequantia modo simplicia, modo ad basin usque bipartita exseruntur, modo singula modo plura, modo in anteriore modo in posteriore cor- poris parte. Haec per plures dies propendent, dum animal, alioquin segnissimum, multo alacrius in vitro suo circumvagatur. Simul sub- stantiae floccosae albidae magna copia secernitur, totam mox vasis in quo servantur aquam turbidam reddens. “ Inter phaenomenon hoc etpropagationem relationem quandam exis- tere, nullus dubito ; plurimas enim Cleps. complanatas per tria semestria domu observavi, neque vero alio unquam tempore organa haec filiformia eas exserere vidi, dum amoris tempore ne una quidem inter triginta et plures non exserebat. Praeterea his organis exsertis, ut in Cleps. tessulata post coitum, ovariorum motus peristalticus, quo ova a funi- culis suis solvuntur, incipit. Quo vero munere fungantur haec organa, nescio ; anatomica quoque disquisitione nihil de eo docente. Nam cor- pora quidem in crura dua reflexa divisa in tertio quovis annulo utrin- que sub tractus intestinalis appendicibus latentes reperi, quibus replicatis organa illa filiformia fortassis formantur; num autem cum testiculis, quibus interjacent, aliave apparatus sexualis parte cohaereant, videre haud contigit. “ Corpora similia etiam in C. verrucata, marginata, tessulata, inveni, quamvis in nulla praeter complanatam specie organa filiformia exseri vidi.” MAX SCHULTZE. Zoologische Skizzen. Zeit. f. w. Zool. IV. 1853. pp. 186, 187. “ Höchst auffallend ist, dass bei Planaria torva der Same in festen, retortenförmigen Spermatophoren verpackt übergeführt wird, welche man ein oder zwei an der Zahl nach der Begattung in dem beschriebe- nen Raume [recept. sem.] findet. Die aus einer braunen, chitinartigen Hülle bestehenden Spermatophoren platzen später, und fallen nach Entleerung des Inhaltes ganz zusammen. In diesem Zustande kann man sie im ersten Frühjahr bei fast jedem Individuum dieser Species sehen. Ich erinnere hier an die Beobachtungen von Fr. Müller (.Zei- 1 Nisi forte appendiculae generatrices a Morrenio {De Lumbr. terresti', p. 77) sic dicta, quas in Lumbrico terrestr. auctor laudatus, in aliis pluribus Lumbricinis Cel. Dr. Hoffmeister et ipse observavimus, Cleps. complanatae organis filiformibus analogae. 3 66 WHITMAN. [Vol. IV. tung für Zoologie etc. von D'Alton und Burmeister, No. 2p, Juli, 184g), welche ich selbst bestätigen kann, dass bei Clepsine complanata und wahrscheinlich bei vielen Regenwürmern die Begattung durch Sperma- tophoren vermittelt wird." A very important observation was made by Filippi, and con- firmed by Grube; namely, that individuals isolated for some days before oviposition produced fertile eggs. This fact and the absence of a penis suggested self-fertilization (Filippi), or possibly an early internal fertilization (Grube). F. DE FILIPPI. Lettera sopra 1’ Anatomia e lo Sviluppo delle Clepsine. 1839. P- 15- “ Tutti i zoologi si accordano nel dire che le sanguisughe sono er- mafrodite ; il che è vero anche per riguardo alle Clepsine ; ma in queste gli organi de’ due sessi sono totalmente diversi che negli altri generi della famiglia. E anche ammesso da tutti che le sanguisughe non pos- sono fecondarsi da se, ma hanno bisogno del reciproco congiungimento di due individui ; e qui mi occorre di far rimarcare un’ eccezione che ci presentano le Clepsine. Infatti per le condizioni speciali de’ loro organi generativi non può nemmeno aver luogo in esse una fecondazione inte- riore ; al che si aggiunga aver io /’ es sempio di un individuo, il quale mantenuto isolato in un vaso di cristallo nella mia camera partorì uova che in seguito si svilupparono.” ADOLPH EDUARD GRUBE. Untersuchungen ueber die Entwicklung der Clep- sinen. Königsberg, 1844. P- n. “ Gegen die Vermuthung, dass sich die Clepsinen äusserlich selbst befruchten, spricht der Umstand, dass ich an den frischgelegten Dotter- kugeln oder in der Eiflüssigkeit nie Spermatozoen gefunden, was doch, wenn die Samenflüssigkeit mit den Dottern zugleich ausgeschüttet würde, kaum anders sein könnte, gegen die Annahme in’s Besondere, dass sie sich äusserlich gegenseitig befruchten, der Beweis, dass wenn ein mehrere Tage abgesperrtes Individuum Eier legte, diese sämmtlich zur Entwick- lung kamen. Vielleicht also erfolgt die Begattung doch innerlich, aber zu einer frühem Zeit? In diesem Fall müsste sie wenigstens n Tage vor dem Eierlegen eintreten, denn so lange hatte ich eine Clepsine abgesondert, deren Eier sich vollständig entwickelten, und die Enden der Samenleiter müssten dann sich umstülpen und als Ruthen dienen, oder die Spermatozoen gelangen in besondere Behälter geschlossen in die weiblichen Genitalien.” No. 3.] SPERMA TO PH ORES. 367 RUDOLF LEUCKART. Die Menschlichen Parasiten. I. 1863. pp. 675-680. The place and mode of origin, and the form of the spermato- phore were long ago correctly described by Leuckart. Speaking of the terminal double sac of the male organs of the Rhynchob- dellidae, he says : — “ Der körnige Inhalt derselben dient zur Umhüllung des Samens und formt denselben im Innern des Begattungsapparates zu einer gleichfalls zweihörnigen plumpen Spermatophore, die bei der Begattung in die weib- liche Oeffnung eingeschoben wird." [pp. 675, 676.] Leuckart assumes that in such forms as Clepsine there is direct copulation, — that is, by union of the sexual orifices, — and further, that fertilization is reciprocal (p. 673). But Leuck- art has also seen spermatophores attached to the external pore of the female organs ; for he says : — “ Wo eine eigentliche Scheide fehlt ( Bei den Rüsselegeln), da wird die Spermatophore in der weiblichen Oeffnung festgeklebt. Man sieht sie hier noch halbe Tage lang nach der Begattung ansitzen, bis die Sper- ma tozoen in den Eierstocksschlauch übergetrieben sind. Auch bei den Arten mit Scheide findet man die Samenfäden später im Innern der Eierstock." [p. 680.] 2. Clepsine tessulata. F. MULLER. Über die Geschlechtstheile von Clepsine und Nephelis. Miiller’s Archiv. 1846. p. 145. “Mit dem Fusse festsitzend saugt jedes der beiden Individuen mit dem Kopf sich an der Bauchseite des andern fest, worauf ein konisches Organ ans der vordem Geschlechtsoffnung sich ausstülpt und in die hintere des anderen Thieres eintritt; so vereinigt sitzen die Thiere meist mehrere Tage lang.” C. tessulata, if Müllers observation be correct, takes an excep- tional position, which is all the more difficult to explain, as C. marginata, and a number of other closely allied species found in America and Japan, certainly all agree in the habit of attaching their spermatophores to the exterior. 368 WHITMAN. [Vol. IV. 3. Clepsine var. Porte-chaine. Moq.-Tand. 1846. PI. xiv. Fig. 5. ÉBRARD. Nouvelle Monographie des Sangsues Médicinales. Paris, 1857. “ Aux derniers jours du mois de mai, en 1854, j’ai trouvé deux glossi- phonies (variété dite Porte-chaine) qui étaient accouplées. Elles étaient fixées, téte à téte, à la face inférieure d’une pierre par leurs ventouses qui étaient très-rapprochées. Leur corps était contourné de telle sorte qu’un de ses cótés touchait la pierre, et que l’autre était libre ; elles étaient accolèes par la surface abdominale. Une seule de ces annélides fécondait l’autre ; car, les ayant séparées, je qu’une verge. Les ovaires de l’une d’elles se gonflérent et se colorèrent peu à peu en blanc, et quarante-cinq jours après elle fit des ceufs." [pp. 60, 61.] Ébrard had the question of reciprocal fecundation in mind, and entirely overlooked the spermatophores. 4. Clepsine marginata. C. O. WHITMAN. The Embryology of Clepsine. 1878. pp. 8, 9. “ I have found that eggs taken from the ovary at the time they are about to be laid develop in the normal manner, and have taken advan- tage of this to watch the earliest changes in the ripe egg. I have done this many times, and always with success. I regard this as very strong evidence that impregnation takes place while the eggs are iti the ovaries. This is in harmony with the fact that I have found spermatozoa in the ovary two or three days before the time for depositing the eggs. It is barely possible that these spermatozoa found their way into the ovary accidentally during the dissecting. I can only say that no testicular sacs were ruptured during the process ; but the vasa deferentia may have been severed, as they are so minute that one cannot easily see them. The unchanged condition of the germinal vesicle at the time the eggs have attained their full size renders it probable that fecundation does not take place more than four or five days at the longest before the deposit ; but this does not prove that copulation may not have taken place at a much earlier date. I isolated an individual which had just sucked itself full of blood, and which showed no signs of eggs through the body-wall, and after fifteen days obtained eggs that developed in the usual manner. Recalling the fact that the growth of the egg from the primary egg-cell requires only twelve to fifteen days, it appears that this specimen was isolated about, or just before, the time when the egg-cell began to grow. In another case eggs were obtained at the end of twelve days, which developed in the normal way. No. 3.] SPERMA TO PH ORES. 369 “These facts raise a suspicion that Clepsine is capable of self-fecun- dation. The question as to whether copulation occurs will be most satisfactorily settled by isolating young individuals and keeping them until they produce eggs. May 2, 1878. — “ Five individuals were isolated in the summer of 1877, at the time of hatching. Each has been kept in a separate vessel from that time to the present. Eggs were laid by one April 24th (this year), and hatched May ist; by two others, April 29th. The latter are now in the germ-band stage. The eggs had in each case passed the pronuclear stage, at the time they were first noticed, so that I was unable to demonstrate by section the existence of a male pronucleus. As the eggs developed in the normal manner, it is very probable that they were fecundated. Here is an unquestionable case of self-fructification, or of parthenogenesis— more probably the former.” The above statements not only confirm the observation of Filippi and Grube, as to isolated individuals producing fertile eggs, but they also make it probable that fertilization is inter- nal. To the evidence given by eggs taken artificially from the ovaries, I can now add another which seems to be perfectly conclusive. I have succeeded in finding a perfectly distinct and indubitable male pronucleus in the ripe ovarian egg of C. marginata. What I formerly regarded as positive proof, either of self- fructification or of parthenogenesis, in the light of what I now know about the use of spermatophores, is open to some doubt. At the time of my experiment of rearing individuals from the egg in isolation, the possibility of hypodermic impregnation never crossed my mind, and I can now see where my observa- tion was not sufficiently guarded to remove all doubt. In order to bring the five individuals to maturity, I had to feed them some ten or twelve times. I allowed them to take their meals from the same fish, only thinking it necessary to watch them from beginning to end, in order to see that no copulation took place. Whether I ever allowed them to come in contact long enough to deposit spermatophores, my notes do not show, and here is where the doubt comes in. The experiment ought to be repeated under conditions that would exclude every possibility of contact, and C. marginata would be one of the best species for such a purpose, as it is so easily reared. It would be well to isolate a large number of individuals, so as to have material 370 WHITMAN. [Vol. IV. enough to allow of taking the ripe eggs from the ovaries in a few cases. The demonstration of the male pronucleus in such eggs would show that the leech is able to fertilize itself inter- nally. If the male pronucleus were not found before oviposi- tion, and should be found some time after it, one could infer external self-fecundation. If the male pronucleus proved to be wanting in both cases, we should have conclusive evidence of parthenogenesis, provided a considerable number of tests all gave like results, and provided, further, that the rest of the eggs developed embryos. The importance of the experiment will be readily seen ; for should self-fertilization be clearly proved under the conditions named, I think that fact, in the light of what we know about the breeding habits, would be sufficient to make it extremely probable that self-fertilization is a normal affair. That view would compel us to look upon the spermatophores attached to the surface as having nothing to do with fertilization. While self-fertilization certainly seems very improbable, we are not to forget that it is a possibility. It is believed to take place in Cestodes, and perhaps also in some Trematodes and Turbellaria. V Baer (Mül. Arch., 1835, p. 224) long ago reported a case in Limnceus auricularis, and Oken (Isis, 1817, p. 320) obtained fertile eggs from an individual of the same species reared in isolation. 5. Nephelis. ISAO IIJIMA. Origin and Growth of the Eggs and Egg-strings in Nephelis. Quart. Jour. Mìcr. Sci. N. S. LXXXVI. April, 1882. pp. 196-197. “ The anterior portions of two individuals, attached by their suckers to the glass vessel near each other, are spirally entwined in such a manner that the ventral surfaces of their genital bands are always brought into apposition. They maintain this position for a considerable time, now and then changing the direction of their winding, and relax- ing or tightening their hold. Sometimes the act is of short duration, and two or three times renewed at short intervals. At other times, and when disturbed, the act ceases altogether, or else they combine with other individuals. It is evident that there can be no reciprocal fecunda- tion while the leeches are coupling in the position above described. “ As there is no intromittent organ, it is probable that the male orifice with its prominent muscular lips clasps the female orifice, while the sper- matozoa are forced onward by the action of the ejaculatory organ. No. 3.] SPERMA TO PH ORES. 371 “ I am unable to say precisely at what time of the year copulation begins ; but I found spermatozoa in the ovaries of one leech on the 20th of February, for the first time in this year. The act of coupling, so far as my experience goes, takes place almost always in the morning. “ Abnormal Copulation. — I have often found individuals with a small, two-horned, whitish body adhering to some portion of the genital band. The position of this cornuous body was always on or near the genital band, sometimes on the dorsal surface, sometimes on the extreme margin, but more frequently on the ventral surface than elsewhere. It consisted of two thin-walled bottle-shaped tubes (ca. 5 mm. long), the broader ends of which were inserted, close to each other, into a small disc-like portion. This portion, the margin of which presented a villiform appearance, was partially einbedded in the epidermis. Around the disc was a discolored area, which proved to be, on examination of sections, a macerated portion of the epidermis. The two bottle-shaped tubes were filled with spermatozoa, and opened by means of two distinct holes in the disc. From each of these openings a stream of spermatozoa was found, penetrating to a considerable depth into the underlying tissues. In sec- tion the substance of the two-horned body appeared dotted and longi- tudinally striated, but I was unable to recognize any cellular structure. “ For a long time I was much puzzled as to the meaning of all this, but from further observation was led to regard it as a case of abnormal or unsuccessful copulation. “ When disturbed during the act of copulation, the two leeches usually separate immediately ; but in one instance they did not separate even after putting them into chromic acid. Oil examination I found that the female orifice of each leech was not in contact with the male orifice of the other, but that each individual was attached to the ventral surface of the other by its male orifice, the female orifice remaining free. On sepa- rating them by force, each male orifice left the two-horned object on the body of the other. “ In another instance that came under my notice, only one individual had already deposited the two-horned body, while the other had a mass of spermatozoa hanging from its male orifice. The latter was dissected, and the two-horned body found occupying the whole interior of the ejaculatory organ, with the cavity of which it exactly corresponded in shape. It came out without any resistance. It thus became evident that the two-horned body belongs to the interior of the ejaculatory organ. That it forms no permanent part of the male organ seems evi- dent, from the fact that sections made in the winter show no trace of such a body. I have not thus far been able to determine whether this body forms in the case of normal copulation also. As to its mode of 372 WHITMAN. [Vol. IV. formation, I have nothing to offer except the conjecture that it may be the hardened secretion of some of the glands of the ejaculatory organ. “ On many leeches were found scars, which very likely may have been the marks left by these peculiar bodies. “ It is hardly to be doubted that the normal mode of charging the ovaries with spermatophores is through the female orifice. It would certainly be impossible for the spermatozoa to find their way into the ovaries in many of those cases which we have described as abnormal, especially where the injection takes place far in front of the male orifice.” Professor Iijima’s observations were made under my direction, and at the time I certainly concurred with him in his conclu- sions. Professor Iijima’s incredulity was wholly due, as one may readily see from his own words, to the conviction that there was only one way provided by nature whereby the sper- matozoa could reach the eggs within the ovaries ; namely, through the female genital pore. The whole description tal- lies so closely with what I have seen in Clepsine, that I feel confident that the spermatophores serve the same end in both genera. Schneider’s observations on Nephelis are much less complete than Iijima’s, and spermatophores seem to have entirely es- caped him. ANTON SCHNEIDER. Das Ei und seine Befruchtung. 1883. pp. 22, 32, 65. “ Die Begattung beginnt damit, dass sich die Thiere umeinander winden. Ihre Körper sind dabei gleich gerichtet, so dass immer nur ein Thier mit Samen versehen wird. Eine Ausstülpung des sehr kurzen Penis habe ich nicht beobachtet. Bei der Begattung geht viel Samen verloren. Moquin-Tandon, gestützt auf eine Angabe von Bojanus, nimmt an, dass die Körper der Hirudineen bei der Begattung entge- gengesetzt gerichtet sind. Indess hat schon Ébrard *) in seinem sehr lesenswerthen Werke die Begattung von Hirudo medicinali mit gleicher Richtung der Körper vor sich gehen sehen. Auch Iijima hat dies bei Nephelis bestätigt. Man kann die Begattung leicht beobachten. Wenn man zwei Thiere, welche 3-4 Tage isolirt waren, vereinigt, findet die Begattung sofort statt. Bei der von Iijima beobachteten Species findet ausser dieser Begattung eine andre Art statt, indem Spermatophoren von dem einen Thiere auf die Haut des andern befestigt werden. Bei unsern Nephelis habe ich diese Spermatophoren nie gesehen, obgleich mir das Vorkommen dieser Körper bei Pontobdella und Piscicola wohl bekannt ist.” No. 3.] SPERMA TO PH ORES. 373 6. Piscicola. J. LEO. Verhältnisse der Piscicola geometra. Müller’s Arch, f Anat., etc. 1835. p. 425. “ Die Begattung dieser Thiere geschieht auf folgende Weise. Die Fussscheiben zweier Individuen sind in einiger Entfernung von einander auf einer Ebene angeheftet und die Körper erhalten sich schwebend an den äusseren Öffnungen der Geschlechtstheile dergestalt Bauch an Bauch mit einander verschlungen, dass sie die Form eines X bilden, wobei aber das Kopfende jedes Thieres nach derselben Seite zurückge- bogen ist, an welcher seine Fussscheibe haftet. Hinter der Umschling- ung sind beide Körper bedeutend angeschwollen und dicht vor dieser Anschwellung sieht man in der Nähe der weiblichen Geschlechtsöffnung eine weisse Masse hervortreten, die sich nach und nach vermehrt, und unter dem Microscope sich als ein Säckchen mit einer weissen, feinkör- nigen und schleimigen Substanz erfüllt darstellt. Ich glaube, dass diese Masse ohnerachtet des häutigen Ueberzuges dennoch nichts anders als der aus den weiblichen Geschlechtstheilen Überfliessende männliche Same ist, dessen Oberfläche aber wahrscheinlich durch den Einfluss des Me- diums zu einer Haut gerinnt. Dass die Ruthe in die weibliche Geschlechtsöffnung eindringt bemerkt man erst, wenn sich die Thiere von einander durch bewirkte Störung trennen, in welchem Falle dieselbe dann eine Zeit lang steif hervorsteht, wie es abgebildet ist.” Leo’s description of the spermatophore falls considerably short of being a discovery, and his remarks about the penis are wide of the mark. He seems to have mistaken the proboscis for a penis, as Leydig has pointed out. T. BRIGHTWELL. Ueber die Hirudo geometra, Linn., und einige andere Arten von Susswasser-Egeln. Froriep’s Neue Notizen. XXII, No. 467. 1842. p. 65. Somewhat later than Leo, Brightwell again saw the sperma- tophore of Piscicola (“weisse Substanz”), but without under- standing it. During copulation, as Brightwell puts it, “ Man bemerkte auf jeder Seite des Theils, wo die Körper ihre Verei- nigung bewirkten, eine weisse Substanz. So blieben die Thiere gewöhnlich mehrere Stunden, in einem Falle sogar den ganzen Tag ueber verbun- den. Als sie sich von einander trennten, löste sich von den Stellen, mit denen sie aneinandergehangen hatten, eine weisse, spinnewebenartige Substanz ab, welche sich in einem Falle wie ein Ei ausnahm, sich aber bei fernem Beobachtungen als ein Theil des Haütchens herausstellte, 374 WHITMAN. [Vol. IV. von welchem die Eier umhüllt sind. Innerhalb 24 Stunden nach dem Begattungsacte wurden Eier gelegt.” FRANZ LEYDIG. Zur Anatomie von Piscicola geometrica mit theilweiser Ver- gleichung anderer einheimischer Hirudineen. Zeitschr. f.w. Zool. I. 1849. P- I24- “ Bei der Begattung stülpt sich aus der männlichen Geschlechtsöffnung eine Blase, welche die Ausmündungsstelle der Ductus def., sowie einen Theil der gelappten Drüse enthält. Dieser hervorgestülpte Theil gibt an die weibliche Geschlechtsöffnung die Samenmasse ab, welche als weiss- licher Körper auch nach der Begattung an der weiblichen Genitalmünd- ung sitzen bleibt. Die weissliche Masse, näher untersucht, erweist sich als eine gedoppelte Blase mit doppeltem Stiel, an welcher die Membran und die Stiele als aus dem Secret der gelappten Drüse bestehend, erkannt werden. Im Innern sind die Spermatozoiden in schön gelock- ter Weise geschichtet enthalten, so dass man wohl den ganzen weissen Körper als Spermatophoren bezeichnen kann. Schon im Ductus def. brünstiger Individuen lagern sich die Spermatozoiden zu solchen gelockten Bündeln zusammen, wie man sie nacher in den Spermato- phoren findet. Es braucht also nur das Secret der gelappten Drüsen die Spermatozoiden bei der Ejaculation zu umhüllen, um die treffenden weissen Körper zu bilden. Aus den Spermatophoren, welche halbe Tage lang nach der Begattung an der weiblichen Geschlechtsdffnung sitzen bleiben, bewegen sich die Spermatozoiden in den Eicrstocksschlauch und dringen bis zu dessen blindem Ende vor. Ein solcher Eierstock mit eingewanderten Spertnatozoiden hat ein schon dem blossem Auge wahr- nehmbar verändertes, weissliches Aussehen.” Schneider confirms Leydig’s account, and adds Pontobdella to the list of leeches which attach their spermatophores to the exterior. The definite location of the spermatophores in Pis- cicela is noteworthy, in comparison with Nephelis and Clepsine. Leydig assumes that the spermatozoa pass through the female genital pore into the ovaries ; but he gives no proof of this. Per- haps his persuasion that it must be so, was the only reason he had for concluding that it was so. Schneider expressly states that the spermatophores of Pontobdella are attached to any point of the exterior except at the genital pore. ANTON SCHNEIDER. Das Ei u. seine Befruchtung. 1883. pp. 32, 65. PiscicoLA geometrica. — “ Zwei Exemplare heften sich mit dem hintern Saugnapf fest, in entgegengesetzter Richtung und in der Ent- fernung, dass sie sich mit dem Vorderende erreichen können. Sie No. 3.] SPERMA TO PH ORES. 375 krümmen das Vorderende und haken sich in einander. Solange die Reife der Eier nicht eingetreten, ist dies nur ein Vorspiel der Begattung, denn man findet in den Eileitern keinen Samen. Dagegen werden bei dieser Gelegenheit Spermatophoren abgesetzt, welche man häufig auf dem Boden der Gefässe findet.” 7. Pontobdella. SCHNEIDER, Ic. “ Die Spermatophoren von Piscicola und Pontobdella sind kurze keu- lenförmige Röhren, deren Wand aus agglutinirten1 Spermatozoen besteht, während das Innere mit freien Spermatozoen erfüllt ist. Leydig hat dieselben bei Piscicola entdeckt und auch nachgewiesen, dass sie bei der Begattung an die weibliche Ges chiedi tsöffnung befestigt werden. Wie schon oben bemerkt, werden diese Spermatophoren schon gebildet und abgelegt zu einer Zeit, wo die Thiere noch nicht geschlechtsreif sind und kein Samen in die Eileiter eintritt. Man findet die Spermatophoren dann auf dem Boden der Gefässe, worin die Thiere leben. “ Aehnlich wird die Begattung bei Pontobdella vor sich gehen. Zur Zeit als ich Pontobdella lebend beobachtete [April in Triest], fand keine Begattung, sondern nur das Absetzen von Spermatophoren statt. Die Thiere befestigten sich dieselben gegenseitig an beliebige Koiperstellen, nur nicht an die Gesell lech tsö ffn u ng. ’ ’ 8. Hirudo. The ten-eyed leeches (Hirudo, Aulostoma, etc.) all have a well-developed intromittent organ, and observers now agree that in copulation the male organ of one individual is inserted in the female orifice of the other, and that fertilization is one- sided, not reciprocal. No one, so far as I know, has ever reported external spermatophores, and there is no reason to suppose that hypodermic impregnation ever occurs in the Gnath- obdellidae. Some of the older authorities maintained that fecundation was reciprocal, and Moquin-Tandon, as late as 1846, declared this to be a settled fact. Ébrard, however, disputes this point, and brings many facts to show that only one indi- vidual is fertilized at a time. Perhaps the conflicting testimony warrants the suggestion that fecundation may sometimes be reciprocal, at other times not. If copulation happened between two individuals equally ready to fecundate reciprocally, there 1 An error corrected by Vejdovsky. 376 WHITMAN. [Vol. IV. would be no difficulty in their doing so, provided the position taken were such as to admit of it. On the other hand, if one individual only were ready to discharge the male function, only one individual would be fecundated. I incline to take this view, as it offers a complete reconciliation of otherwise contradictory observations. Ebrard’s experiments in isolating leeches are not only inter- esting per se, but also in connection with the results before given of isolation of Clepsine. A. MOQUIN-TANDON. Monographie des Hirudinées. 1846. pp. 166-68. “ Bibiéna, Thomas, Vitet, Mérat, Derheims et Fée, ont pensé que les Hirudinées se reproduisaient sans accouplement rèciproque. Suivant Filippi, les Glossiphonies seulement sont capables de se féconder toutes seules. “Weser, Cuvier, Carena, Virey et Blainville, ont admis, d’après la structure des Organes sexuels, que chaque individu était incapable de se reproduire sans s’accoupler avec un autre. Leur opinion a été trouvée conforme à la nature, après les observations de Hebb et de Evans de Worcester (cités par Johnson), qui ont fait connaitre que l’acte du coit se passait, chez ces Annelides, de la méme manière que dans les Arions et les Hélices. Depuis cette époque, Kuntzmann, Bojanus, Odier et plusieurs autres naturalistes, ont eu l’occasion de voir des Hirudinées au moment de l’accouplement, et ont confirmé les observations des deux savants anglais. “Dans F accouplement des Sangsues médicinales, deux individus se rapprochent, ventre contre ventre et en sens inverse, de telle sorte que la ventouse orale de chacun est tournée, ou à peu près tournée, vers la ventouse anale de l’autre. On congoit que, dans cette position respec- tive, les Organes génitaux se trouvant également situés en sens inverse, de manière que chaque verge doit se rencontrer en face d’une vulve. Les deux individus s’enlacent, et l’accouplement a lieu (Bojanus). Quelquefois les Sangsues s’attachent ensemble par leurs ventouses anales et laissent pendre librement leur partie antérieure (Burdach). Kuntz- mann a era reconnaìtre que, dans l’union sexuelle, les deux verges sont entortillées en spirale comme celle des Hélices ; cette disposition est sans doute accidentelle (Bojanus). “ Le docteur Gaspard a prétendu que, dans chaque accouplement, un seul individu fécondait l’autre, lequel, après vingt-cinq ou trente jours, fécondait le premier dans un autre accouplement. Il est bien démontré aujourd’hui, par l’observation, que le coit est rèciproque comme celui des Escargots. No. 3.] SPERMA TOPHORES. 377 “Johnson a observé Paccouplement de la Néphélis, et a reconnu qu’il était entièrement semblable à celui de la Sangsue medicinale." ÉBRARD. Nouvelle Monographie des Sangsues Médicinales. Paris, 1857. pp. 104, 105. “Comment se fait-il done que Bibiéna, Thomas, Vitet, Mérat leur aient accordé la faculté de se reproduire sans accouplement préalable ? I Is ont probablement è tè trompès par cette circonstance qu'une sangsue produit des cocons féconds trois, six, huit, et méme dix mois après avoir è tè tenue iso tèe. C’est là un fait dont il ne m’est pas permis de douter, quoique l’intervalle séparant l’accouplement des sangsues de la pose ou production des cocons ait été évaluée par divers auteurs à trente ou quarante jours. “ J’ai déjà publié, en 1851, l’histoire d’une sangsue verte de Hongrie qui, renfermée seule vers le 15 mai 1850, produisit le 15 et le 27 aout des cocons féconds. “En 1852, soupgonnant que les cocons de sangsues ne donnant pas le jour à des filets proviennent (de méme que cela arrive pour les oeufs stériles des femelles d’oiseaux tenues en cage) de sangsues ne s’étant pas accouplées, et, voulant m’en assurer, je piagai, le 15 septembre, sept sangsues vaches dans autant de bocaux contenant de la terre et de la mousse, une sangsue dans chaque bocal (je les gorgeai et je les changeai de terre en mars (1853). Six de ces sangsues posèrent des cocons aux mois de juillet et d’aout suivant, c’est-à-dire après neuf à dix mois d'isolement, et, à mon grand ètonnement, des filets sortirent de ces cocons. “ En face de ces résultats si inattendus, je me demandai, je l’avouerai franchement, si les sangsues, tout en s’accouplant, ne pouvaient pas produire des cocons sans un accouplement préalable, ou plutót si un rapprochement ne suffisait pas pour plusieurs années. Je me livrai, en conséquence à de nouvelles expèriences : — “ i° Je continuai à tenir séparés quatre des sangsues précédentes qui étaient isolées depuis un an, et deux autres sangsues qui l’étaient depuis deux mois, depuis le mois de juin, et avaient récemment posé des cocons; toutes furent stériles l'année suivante, quoique j’eusse pris soin de les gorger légèrement aux premiers jours du printemps. “ 2° Je réunis, le 17 septembre, trois des sangsues ayant été tenues isolées depuis un an, puis je les séparai le 20 octobre. Je séparai le 17 septembre quatre autres sangsues qui étaient renfermées depuis quelque temps dans le méme bocal. Une de ces sangsues périt, cinq des autres posèrent des cocons féconds pendant les mois d’aout et de juillet de l’année suivante. “ Il est dès lors évident, ce me semble, que les sangsues ont besoin de 378 WHITMAN. [Vol. IV. s' ac coupler chaque annèe pour ótre fècondèes, mais que, semblables en cela à plusieurs insectes, dies peuvent ne se reproduire que huit ou neuf mois apr'es avoir été fècondèes. Ce fait de la reproduction ayant lieu dans une annèe autre que celle de l ’accouplement a d ’ailleurs son ana- logue chez une hirudinèe non mèdicinale ; car les glossiphonies [Clepsine] que, aux premieres chaleurs du printemps et peu de jours après leur sortie de leur retraite hivernale, portent souvent dèjà des oeufs sous Vabdomen, ont certainement ètè fècondèes dans l’annèe précédente." 9. Aulostoma. EBRARD, l.c. p. 67. “ Deux aulastomes que j’ai trouvées accouplées étaient rapprochées téte à téte. Une seule fécondait l’autre ; car je n’aperqus qu’une seule verge lorsque je les séparai. L’une d’elles posa son premier cocon, ceuf polysperme, quinze jours avant l’autre annélide.” 10. Macrobdella. Copulation has not, so far as I know, been observed in our common Macrobdella. That copulation occurs there can be little doubt. These leeches are remarkable for having so-called “ copulatory glands,” opening on the ventral side, a few rings behind the 9 pore. It was Leidy who suggested that these glands are “ provided for the adherence of individuals in sexual intercourse,” and their position supports this view. This pecu- liarity makes it all the more desirable to witness the process of copulation. From what we know of other leeches, it is proba- ble that individuals captured in early spring, and kept some days in isolation, would, on being brought together, very soon copulate. Observations on Clepsine plana (n. sp.). The specimens on which my observations were first made were two large species obtained from Charles River, at Water- town, near Cambridge, in September, 1884. I am unable to identify them with any species hitherto described. Five of the nine individuals captured were dark brown, variously marked with yellow above, and with twelve or thirteen longitudinal lines below ; the remaining four were yellowish brown both above and below. No. 3.] SPERMA TO PH ORES. 379 Clepsine parasitica, as described by Say1 and Verrill,2 agrees in certain features closely with the dark species, and Verrill’s C. papillifera var. carinata may be identical with the light species. The descriptions, however, do not point out any char- acters which can be relied upon for identification. The dark specimens, to be described in the following paper under the name C. plana, were ready to copulate whenever they met ; but they always avoided the light species, which may be provisionally designated as C. carinata. The latter showed no disposition to copulate until early the following spring. They remained quiet during the winter ; but on being started up in May, they began to deposit sperm-cases. The observations which follow are confined mainly to C. plana. Two of this species bore young still stuffed with yolk, and another had eggs in its ovaries that were nearly mature. When I first placed these Clepsines in a dish together, I noticed several long white bodies attached by one end to the dorsal surface of one or two individuals. I pulled them off for examination, thinking that they were parasites of some kind. Putting them under the microscope, I saw, to my great surprise, a stream of spermatozoa slowly issuing from the end that had been detached. At first I could hardly believe that these sperm- cases belonged to the leech, never having detected the animal in the act of depositing them, and not suspecting that they could discharge their contents through the skin. My curiosity having been thus aroused, 1 watched the leeches more closely, and soon had an opportunity to see the whole operation. The leeches were moving about as they usually do when first cap- tured, before becoming wonted to new quarters. One indi- vidual, coming in contact with another, fixed itself by its oral sucker to some convenient point, and then, while pressing its protruded male pore against the back of its fellow, planted a fresh sperm-case. During the operation, which lasted only a few seconds, the body in the region of the genital pores was more or less constricted, somewhat as it is in the act of forming an egg-cocoon. The constriction seemed to be the expression 1 Thomas Say: Major Long's Expedition to the Source of St. Peter's River, etc., in 182g. Voi. II, Appendix, p. 14. Keating’s Compilation, London, 1825. 2 A. E. Verrill: Synopsis of North-American Fresh-water Leeches. Professor Baird’s Report for 1872-73. 380 WHITMAN. [Vol. IV. of an effort to press the sperm-case firmly to the surface of attachment, and very likely the case was filled with spermatozoa by the same act. After a few moments of steady pressure, — just long enough to allow the sticky secretion to “set,”—the leech released its head and slowly drew back, allowing the spermatophore to be gradually pulled out of the two sac-like ends of the vasa deferentia. I saw this operation repeated several times by the same individual at intervals of about thirty minutes. Among twenty or thirty spermatophores, I found only one on the ventral surface, and this was near the margin of the body ; the rest were attached to the dorsal side, sometimes between two rings, sometimes in the middle of a ring, without any dis- crimination of place, so far as I could see. Although the sperm-case is formed in two distinct sacs, unit- ing in a common pore, its two halves are firmly glued together, as the result of being pulled out through the single pore, while they are still in an adhesive condition. The moment they are set free, they are hardened by the action of the water, and only the small free ends sometimes remain distinct and separate. One of the spermatophores first deposited measured 8 mm. in length and i mm. in width. Some of the last obtained meas- ured only 3 mm. or even less. Repetition of the act seemed to exhaust the individual’s power of forming spermatophores. Widely as they varied in size, they always showed essentially the same form as that shown in Fig. 4, a and b. In the spermatophore we may distinguish (1) a short, con- stricted, basal portion with a single tubular lumen, formed in the median unpaired portion of the male organs ; (2) an elongated body with a double saccular lumen, formed in the enlarged end-portions of the vasa deferentia communia ; and (3) a free end, consisting of two distinct parts, adherent or separate, with lumen closed, or reduced to a narrow line, formed in the ends of the ejaculatory ducts (d) at the point marked w in Fig. 5. The wall of the spermatophore, which is thickest at the base and thinnest in the saccular body, is composed of two well- defined layers : an outer, thin, transparent, finely striated, non- stainable, cuticular-like layer (Fig. 2, o), which appears to fill the angles between the two halves of the case (Fig. 4 b), and to serve as a medium whereby the case is firmly glued to the No. 3.] SPERMA TO PH ORES. surface ; and an inner, denser, thicker, stainable layer (Fig. 2, i). The outer layer is so extremely thin over the saccular portion of the fresh spermatophore that it is difficult to recognize it ;1 but it is easily demonstrated on sections. In the basal portion, this layer thickens, and then expands to form a broad base, so closely applied to the underlying cuticula as to form almost a continuum with it (Fig. 2). The striations of this layer may be due to the pull given to the sac as it is liberated from the genital pore, or more probably, as I think, to its mode of forma- tion by numerous gland-cells. When first placed, the spermatophore usually stands nearly perpendicular to the surface. It is tough and elastic, and con- siderable force is required to detach it. The skin of the leech around the place of attachment is at first strongly corrugated, as if by contraction ; but this appearance gradually passes away after the sac is emptied, although the sacs often remain for several days, or even weeks. Whether they are ultimately dis- solved, or shed with the cuticula, or drop off as the result either of vital processes in the underlying skin, or of the solvent action of water, I am unable to say. The mouth of the fresh spermatophore is completely plugged with a peculiar secretion (Fig. 4, a, gs), made up of elongated ellip- tical or spherical corpuscles (Fig. 4, c), varying from 0.02 mm. in diameter to much smaller dimensions. These bodies dissolve in water in the course of a few minutes. At first appearance, they are coarsely granular, but rapidly become perfectly homo- geneous and transparent, and, growing paler and paler, fade away by insensible degrees. At first I took these bodies to be cells, as some of them appeared to be nucleated ; but having traced them to their origin in glands of a definite region of the vasa deferentia, I now think that the nucleus-like centre (Fig. 4, c) merely marks the depth to which the water had penetrated at the moment of examination. Their great variation in size is also in harmony with their origin as globular secretions. This granular secretion probably serves a double purpose : first, to protect the spermatozoa inclosed in the saccular portion against contact with water ; and secondly, as a means of open- ing and clearing the way for the safer penetration of the sper- 1 Exposed to acetic acid, it swells, and is thus made evident without the aid of sections. 382 WHITMAN. [VOL. IV. matozoa. This mass is expelled through the skin in advance of the spermatic elements ; and the disappearance of the pigment and the clarification of the tissues at the point of penetration, all of which is noticeable in sections (Fig. 2), suggest that it may have a softening effect on the tissues.1 This, however, is pure conjecture. With plenty of material, the action of this secretion on fresh pigmented tissue might possibly be deter- mined experimentally ; but thus far I have not tried this. If the leech is placed under a magnifying power of twenty or forty diameters, immediately after receiving one of the sperma- tophores, one may see the spermatozoa slowly flowing from the narrow mouth of the case through the skin. In the course of an hour the greater part of the contents has escaped, and the case itself is reduced to less than half of its original diameter. As soon as the case is planted, it begins to shrink ; and this con- traction, induced by the action of the water, is probably what forces the spermatic fluid through the skin. When the sac is first placed, the spermatozoa may be seen through the wall united in close bundles. Soon after deposit, as one may see towards the free end of the sac, these bundles begin to swell up, and the indi- vidual spermatozoa begin to show themselves. The appearance might raise a suspicion that a part of the spermatozoa undergo histolytic changes, serving by expansion as a means of expelling the rest, somewhat as described by Gruber in the Copepoda (v. extract). I think, however, that Leuckart’s suggestion in regard to the spermatophore of Astacus is the explanation to be adopted here, as it is perfectly certain that the sperm-case gradually contracts as its contents escape. I find that a few spermatozoa are always left in the case after it has reached the limit of contraction, showing that the expelling force ceases to act after this. As distinct spermatozoa were found in a sperm- sac two days old, I infer that the sac is water-proof. If a fresh sac be detached and exposed to the pressure of a cover- slip, the sperm is rapidly driven out in the form of a white flaky string, consisting of a viscid fluid, with numerous bundles of spermatozoa. In order to learn precisely where the spermatophore is formed, as well as the origin and relative positions of the various ele- ments with which it is to be charged, it will be necessary to 1 Isjima’s observations on Nephelis favor this view. No. 3.] SPERMA TO PH ORES. 383 examine briefly the form, structure, and contents of the male efferent ducts. A glance at Fig. 5 will show that these ducts are differentiated into a number of different regions, each of which seems to have a special function. Beginning with the pore, which lies between the tenth and the eleventh ganglia, we find a very short median tube, which bifurcates beneath the ventral cord, giving rise to two diverging horns (s), which are continued into a convoluted tube (zu, g, d) of nearly uniform, but much smaller, diameter ; then follows an enlarged sigmoid coil (vs), and finally the long narrow tube (vdc), which receives the six short testicular ducts (vd). The sigmoid portion is a thin-walled reservoir completely filled with sperm-bundles, fulfilling the Fig. I. — Section from the posterior half of the ductus ejaculatorius, showing bundles of spermatozoa (sj>) massed together, and a few granular corpuscles (gc), probably secretions from the anterior, glandular half of the duct. The muscular layer (m) is strongly developed, and the large lumen is lined with a thin epithe- lium (ep). office of a vesicula seminalis. The convoluted portion con- necting the vesicula seminalis with the terminal horn-like enlargement (s) appears externally to be a nearly uniform tube, and is usually called the ductus ejaculatorius (d). But an exam- ination of the structure and contents of this portion reveals the fact that it is really differentiated into two parts which fulfil different functions. The posterior half (d) has a thicker mus- cular wall, and a much larger lumen than the anterior half (w and g) ; it is lined with a thin epithelium, and is filled with spermatozoa. In the anterior half this epithelial lining takes the form of long columnar gland-cells, radially disposed, with the 384 WHITMAN. [Vol. IV. nucleated ends next to the muscular wall. The reduction of the lumen in this part is due to the development of this glandular epithelium. It is in this glandular portion that the granular cor- puscles (gc) which plug the spermatophore are produced. I have a series of sections of this region, showing the gland- cells fixed in the very act of secreting these corpuscles. The corpuscles are somewhat pyriform in shape, with the smaller end tapering to a fine thread, which is connected with the cen- tral end of the producing cell (Fig. 2, gc). As soon as the cor- puscle is fully liberated, it assumes a more or less elliptical form. These corpuscles sometimes nearly fill the whole lumen of the duct ; sometimes they lie in masses that resemble clusters of Fig. 2. — Section from the glandular anterior half of the duct, in which the lining epithelium (