1851.] 281 



Prof. Siebold* speaks of Filariac of various kinds of insects, resembling Gordii, 

 wiiich lived for some time in clear water, in which they had been placed. He 

 afterwards discovered the factf that sexes of Gordii were individutlised, 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 Mennis of Dujardin ; the family he calls 

 GoRDiACEyE, 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 Gordiacese, (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 Gordiacese a separate 

 group amongst Nematoidea, on the ground of their embryonic development. 



Mr. DujardiniT 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 diflticulty 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. 



*Wi.egman's Archiv fiir Naturgeschichte, 1837, ii., p. 254. 

 \Wi.fgma7i's Archiv, &c., 1838, ii. p. 292, (on the inogress of Ilelminthology)', 

 and 1838, i., p. 302, {Helminthologisclie Bdtriige). 



I In Germar's Entomologische Zeitung, 1842. 



II Wiegma7i's Archiv, &c., 1843, ii., pp. 302 and 307. 



Entwurf einer systematischen Eintheilung und speciellen Beschreibung der 

 Plattwiirmer, &c., 1S44, pp. 28, 35. 



irHistoire Naturelle des Helminthes ou vers Intestinaux. Paris, 1845, 8vo. 



*Recherches sur I'organisation des vers. Gordiacece. Aunales des Sciences 

 Naturelles, 3d ser. Vol. xii., 1839, p. 5. 



