Historical Sketch of Gordiaceas. 
[From the Proceedings of the Academy of Natural Science of Philada., Vol. V. No. 11,1851.] 
Charles Girard. 
There are groups, amongst the invertebrates of the animal kingdom, whose 
natural history has made but little progress, although known to science for more 
than half a century. 
The animals of which they are composed being generally of a diminutive size, 
modest in form, modest in colors, have been looked at with indifference, thought 
unworthy of a careful investigation, and deemed of too small an importance in a 
general system of classification. 
Every living being, however, is entitled to occupy a rank in the creation ; 
every one has its place, its aim, and its design. 
Yet some are called enigmatic, paradoxical, doubtful,—as if to the Creator’s 
mind, any thing or any being could be either an enigma, a paradox, or a doubt. 
Such groups, we must acknowledge, present great difficulties to investigators : 
but let investigators be patient and laborious, and they will gradually sweep 
away the enigmas, the paradoxes, and the doubts. 
When the researches on a group are slow, and embrace a long period, then it 
becomes necessary, for the safe and future advancement of its natural history, to 
recapitulate all the data in their chronology. These data will become a guide 
into the various desiderata for new observations. 
Most diverse opinions are still entertained concerning Gordiaceae, and import- 
ant zoological questions are still waiting the results of further investigations. 
Are Gordiaceae indigenous in America, or introduced from abroad ? If they are 
indigenous amongst us, are they identical with, or specifically different from, the 
European species ? 
Here commences a labor of comparison between the internal structure and 
external appearance of specimens from both countries. Besides, specimens from 
all the localities of one country should be compared, in order to ascertain the 
number of species. Their embryology and metamorphosis must be traced; their 
habits recorded, in order to enable us to assign a natural position to that family 
in the class of worms. 
If they are introduced on this continent, how, where, and how long since, did 
that event take place ? What is their geographical distribution and progressive 
migration to the places where they are now found ? 
Some facts, which we already possess, and which are related hereafter, rather 
enforce the belief of their aboriginal nature, than that of their introduction. Even 
in the case of an identity between the American and European Gordiacese, these 
worms still deserve special attention from American anatomists, as the 
latter might be successful in elucidating the controverted anatomical questions 
which divide the naturalists of the old world. 
n. 
The genus Gordius was established by 0. F. Muller during the last century.* 
Under that name were included aquatic worms, others living in moist grounds, 
I. 
* Vermium terrestrium et fluviatilium historia, 1773. and still others, more numerous, found as parasites in the body of other animals. 
Those which lead a permanent parasitical life, constitute now the genus Filaria, 
of Ihe same author,* which has been admitted by all subsequent naturalists, and 
more than forty species of these are described by Rudolphi.f But there has been 
a general belief, that the only difference between Gordius and Filaria consisted 
in their habits, no zoological characters having as yet been detected. 
LamarckJ even says, that the species of Gordius were probably Filariae; and if 
he has kept those two genera, it was merely in accordance with a prevailing 
practice. 
Cuvier|| places Gordii at the end of the annelids, thus made to follow the 
leeches, remarking, however, that they might perhaps come nearer the intestinal 
worms. He was unacquainted with the fact, since ascertained, that several 
species of true Gordius may be found, at a certain season of the year, within the 
body of other animals. 
The genus Filaria is placed, by the same author, at the head of intestinal 
worms. Its characters are derived from the external appearance, which, how- 
ever, he (Cuvier) acknowledges, resembles closely that of Gordius. 
Should a generic difference hereafter be found between Gordius and Filaria, in 
their anatomical structure, and we think it very likely to be the case, besides the 
difference of embryonic development which already distinguishes them, we shall 
have that peculiarity in their habits which makes Filaria to occur in such cavi- 
ties of the body of other animals having no communication with the exterior, 
whilst Gordii, when occasionally found within other animals, occur in the intes- 
tinal canal ; that is to say, in a cavity which communicates directly with the 
surrounding medium. This fact is of no small importance. 
The letter of Mr. Jacobson, to de Blainville,§ relates to Filaria, and not to 
Gordius, as its title would lead any one to believe. 
Mr. Charvet,ir in describing two species of true Gordius, thinks that these 
worms are indifferently external and internal, and that the distinction made be- 
tween Filaria and Gordius becomes thus insignificant. But he is inclined to 
believe that, if it can be proved that Filariae have a mouth provided with a suck- 
ing apparatus, the character would be generic. He was not prepared, by direct 
observations, to decide upon this fact. 
Leon Dufour** alludes to Gordii, and rejects the idea of an identity between 
them and Filariae, considering the first as true Annelids, and the second as true 
Entozoa ; there existing, he says, a mere external resemblance, which can only 
be proved to depend on identity of structure by anatomical investigations. 
* O. F. Muller, in Naturforscher. Vol. xxii., 1787. 
f Entozoorum sive vermium intestinalium Historia Naturalis. (3 vol. 8vo., 
1808—1811), Vol. ii. p. 55 et seq. 
t Histoire naturelle des Animaux sans vertebres. Vol. iii., 1809, p. 670. 
|| Le Regne Animal distribue d’apres son organisation, vol. iv., 1817, and 2d 
ed. vol. iii., 1829. 
§ Extrait d’une lettre adressee a Mr. de Blainville sur le dragonneau. Ann. 
Sc. Nat. 2de serie i. 1834. p. 320. 
IT Nouvelles Annales du Museum d’histoire naturelle. Vol. iii. 1834, p. 37. 
** Annales des Sciences Naturelles, 2de serie, vol. vii., 1837, p. 7. Prof. Siebold* speaks of Filariae of various kinds of insects, resembling Gordii, 
which lived for some time in clear water, in which they had been placed. He 
afterwards discovered the factf that sexes of Gordii were individualised, and 
males more numerous than females; and, withdrawing Gordii from Entozoa, he 
places them actually among Annelids. Subsequently! he makes of Gordii a sepa- 
rate family, including also, the genus Mermis of Dujardin; the family he calls 
differing chiefly from that of Nematoidea in its embryonic develop- 
ment. 
Entozoa have that peculiar mode of generation, in which several broods follow 
each other, without resembling each other; nor will they resemble their parent 
stock before the third, fourth, or fifth generation, according to the species. 
The young Gordiaceae resemble their parents as soon as hatched. There is, 
however, not yet a single species of that family whose eggs have been made the 
subject of a careful and complete study. Isolated facts only are known, and 
to these we shall devote a few lines further on. 
There is a phenomenon, with which the naturalists of the old world are well 
acquainted, which takes place during the existence of Gordiaceae, (in Mermis as 
well as in Gordius), it is the fact that they pass one part of their life within the 
body of other animals,—of Grasshoppers and Crickets, for example. They are 
found in the clear running waters of the meadows and fountains, early in the 
spring and summer ; they enter the body of grasshoppers in the fall, where they 
deposit their eggs. These insects die, and their bodies afford to these eggs a 
convenient shelter during the winter, when the next spring they will hatch, and 
become free again.|| Eggs, however, are sometimes found without any such 
nidus; whether naturally or accidentally, remains to be ascertained. 
A. S. (Ersted§ agrees with Prof. Siebold in making of Gordiaceae a separate 
group amongst Nematoidea, on the ground of their embryonic development. 
Mr. Dujardinir is remarkably short, and adds nothing to our knowledge on 
these worms, which he still calls enigmatic. 
The manner in which Mr. Emile Blanchard** has illustrated the anatomical 
structure of the other families of the intestinal worms, would lead us to expect 
from that Observer, more precise facts respecting Gordiaceae, than those we had 
before. But the author, at the outset, tells us that he was unable to fulfil the 
task he had undertaken, that is, a complete history of that family. The want of 
materials in such researches, added to the difficulty of experimenting, are the 
reasons advanced to account for the deficiency in this part of his investiga- 
tions. The subject, therefore, stands precisely as it did before Mr. Blanchard 
undertook his anatomical researches on the class of worms. 
* Wiegma?i’s Archiv fur Naturgeschichte, 1837, ii., p. 254. 
f Wiegman’s Archiv, &c., 1838, ii. p. 292, (on the 'progress of Helminthology')', 
and 1838, i., p. 302, (HeIminthologische Beitrdge). 
Jin Germar’s Entomologische Zeitung, 1842. 
|| Wiegman’s Archiv, &c., 1843, ii., pp. 302 and 307. 
§ Entwurf einer systematischen Eintheilung und speciellen Beschreibung der 
Plattwiirmer, &c., 1844, pp. 28, 35. 
llHistoire Naturelle des Helminthes ou vers Intestinaux. Paris, 1845, 8vo. 
** Recherches sur l’organisation des vers. Gordiacece. Annales des Sciences 
Naturelles, 3d ser. Vol. xii., 1839, p. 5. The last European writer on this subject is Mr. Ed. Grube,* who has made 
some observations on the development of the eggs of Gordius aguaticus, and 
described a new species from Africa. His paper bears chiefly on minute para- 
sitical nematoids. He also alludes to the great resemblance there is between 
Mermis albicans and Ascaris acuminata. 
III. 
The anatomical structure of Gordiaceae is also a matter of much controversy 
amongst anatomists. 
Prof Siebold,f in giving an account of the difference between intestinal worms 
and Gordii, again calls the latter enigmatic. 
Bertholdf describes a system of circulation, neither seen nor acknowledged by 
the authors that came after him. He likewise mentions a nervous system ; but 
giving no further account of it, its characters and distribution in the body of these 
worms remain to be investigated. 
Dujardin|| is in a complete doubt. 
Prof. Siebold,§ in resuming Berthold’s and Dujardin’s investigation, says that 
the organs which Berthold took for veins and arteries, are contracted fibres, and 
that he has failed of seeing any organs which he could confidently call nervous or 
vascular systems. 
We do not know yet the digestive tube of any Gordiaceae. One fact, however, 
is ascertained with regard to that organ: it atrophies in full grown indi- 
viduals. Even the structure of the skin, or external envelope of the body, 
deserves a more full comparative study. 
Although Charvet and Berthold agree in saying that Gordiaceae are androgynous, 
it has been plainly ascertained since, that the sexes are distinct. But the struc- 
ture of the sexual organs is not known. Prof. Siebold found an external charac- 
ter by which males differ from the females, the former, in G. aguaticus, having 
a bjfurcated tail. 
IV. 
Some observations on the development of the eggs of Gordius aguaticus have 
been made by Ed. Grube.1T Dr. Joseph Leidy had made similar investigations in 
1846, and published only in 1850.** The eggs are laid in strings, nearly of the 
length, and sometimes the color, of the worm itself. Within those whitish strings 
or cords are found the eggs. The division of the yolk takes place, according to 
the general law of division of that substance, previous to the formation of the 
embryo. The embryo itself is gradually formed out of the yolk’s substance, in a 
manner similar to that in Clepsinae, and leeches in general. The young resemble 
their parents as soon as hatched. 
*Uber einigen Anguilulen und die Entwicklungs. von Gordius aqvaticus. 
Trosch. Archiv fur Naturgeschichte 1849, vol. i. p. 358. PI. vii. 
f Wiegman’s Archiv, 1838, vol. iv., i. p. 302. 
JUeber das Bau das Wasserkalbs, 1842, in 12. 
|| Annales des Sciences Naturelles. 2de serie, vol. xviii., 1842, p. 142. 
§Wiegman’s Archiv, 1843, ii. pp. 302 and 307. 
IT Troschel fur Naturgeschichte, 1849, i. p. 358. PI. vii. 
**Notes on the development of Gordizcs aquaticus. Proc. Acad. Nat. Sci., 
Philad., 1850, p. 89. Young Gordii possess two circles of filamentary appendages around the pro- 
boscis, which, at this early period, is alternately protruded and retracted. Whe- 
ther the same motion, and the same appendages, are still present in the adult 
state, is yet to be examined. Many worms are known to be provided with a retrac- 
tile proboscis, which they use in perforating the sand and mud in which they 
live. Gordii might require it to introduce themselves into the living bodies 
where they are sometimes found. As to the circles of tentacles, they very likely 
disappear in the adult, while the alimentary canal atrophies, their function being 
intimately connected with the functions of the latter organ. 
V. 
With regard to the species of Gordiaceae to be admitted, naturalists do not any 
more agree. 
The most common in Europe is Gordius aquaticus, L.* The G. marinus and 
G. annulatus of Montague,f are Nemerteae. 
Mr. Charvet} describes two others, from the vicinity of Grenoble, (France,) 
under two trivial names. 
Mr. Dujardin|| considers as distinct, from the above, a species from the vicinity 
of Toulouse, his Gordius Tolosanus, and describes another species, proposing for 
it the genus Mermis, calling the species M. nigrescens. 
Prof. Siebold§ has made us acquainted with a second species of Mermis, his 
M. albicans. 
Mr. BlanchardlT has described one species from Chili, under the name of G. 
Ckilensis. 
Finally, Mr. Ed. Grube** describes another from Africa, which he calls 
Gordius crassus. j 
Before we identify the North American Gordii with any of the above men- 
tioned ones, we must be prepared to account for many objections which can be 
made, respecting their having been created identical over such an extensive area, 
or else of their having migrated naturally, or having been accidentally transported. 
VI. 
We have in the United States one species, which seems quite common in fresh 
water, and referred by some to G. aquaticus. Rev. Z. Thompson, of Burling- 
ton, (Vt.), expresses himself in the following terms : “ The little animal called 
the Hair snake also belongs to this order, (annulata,) and to the genus Gordius. 
* Systema Naturae ed. xii. 1767, p. 1075. 
f Transactions of the Linnean Society of London, vii. 1804, p. 72 and 74. 
t Observations sur deux especesdu genre dragoneau qui habitent dans quelques 
eaux courantes aux environs de Grenobles. Nouv. Ann. du Mus. d’hist. Nat. iii. 
1836, p. 37. Ann. Sc. Nat. 2de ser. ii. 1834, p. 123. Wiegm. Archiv i., i. 
1835, p. 341. 
|| Memoire sur la structure anatomique des Gordius et d’une autre Helminthe 
qu’on a confondu avec lui. Ann. Sc. Nat. 2de ser. xviii., 1842, p. 329 and 146. 
Institut., 1842, p. 256. Archives gen. de Medec. xii., 1842, p. 488. 
§ Entomologische Zeitung, 1843, p. 80. 
H Historia fisica y politica de Chile, por Claudio Gay. Zoologia iii., 1848, 
p. 109. 
** Troschel Archiv, &c., 1849, i., p. 370. These are very common in the still waters, and mud, in all parts of the State. 
They are usually about the size of a large horse hair, and are from one to six or 
eight inches in length. In color they vary from pure white to nearl)r black, and 
hence we probably have several species. The vulgar notion that they originate 
from hairs which fall from horses and cattle, and become animated in the water, 
would seem to be too absurd for contradiction; and yet, absurd as it is, people 
are to be found who believe it.”* 
The same popular opinion is prevailing in Europe. Gordii have been noticed 
in the body of insects, also, by an American entomologist, Dr. Th. Wm. Harris, 
who says: “ I have taken three or four of these animals out of the body of a 
single locust.”f They have been found, by others, within the cricket, (Acheta 
abbreviata). 
We saw a specimen, six or seven inches in length, caught in the clear waters 
in the vicinity of Richmond, (Va.) Several others were detected by Dr. Leidy 
in the neighborhood of Philadelphia. 
Finally, we may mention several specimens of Gordii from Oregon, brought 
home by the U. S. Exploring Expedition. 
Gordii, therefore, are spread all over the Western hemisphere. 
* Natural History of Vermont, 1842, 8vo., p. 170. 
f Report on the Insects injurious to vegetation, 1842, p. 155.