64 RESEARCHEvS IN HELMINTHOLOGY AND PARASITOLOGY. 



thickening of the integument upon the caudal extremity. For this 

 species the name Mermis crassicaudata was proposed. 



Dr. L. further remarked that he had lateh' had an opportunity of 

 repeating his former investigations * upon the embryology of (rordliis 

 variiis. 



The embryology of Gordiiis aquaticus, L., had been studied and 

 published by Gruby t before he had published his notes, but he did 

 not know it at the time, which he considered important, as the ob- 

 servations conducted in two parts of the world, though differing in 

 several points, were generally confirmatory of one another. 



The perfect embr^'O of Gordi7is varius differs so much from the 

 parent that it is impossible to recognize the latter in the former. 

 This has two circles of protractile tentaculae, each of six, and a pro- 

 tractile probo.scis, not uncinate, however, as in the embryo of (lordhis 

 aqi(atici(s,X no trace of which exists in the parent. The body of the 

 embryo consists of two portions, and is distinctly annulated, while 

 the parent is simply hairlike in form, and has no trace of an annu- 

 lated integument. Gruby remarks he never saw the Gordius, ex- 

 cepting the embr\^o, shorter than 3^-4 inches, § so that between the 

 annulose, tentaculated embryo, in the (rordius varies the i -466th of 

 an inch in length, and the parent of at least 2>-4- inches, nothing 

 whatever is known of the history of the animal. Gordii have been 

 stated upon numerous and the most reliable authorities to have been 

 .seen in the body of insects, so that from the embryo to the parent 

 there may probably be a series of forms in alternating generation, 

 entozoic and ectozoic, as numerous and unlike as has been observed 

 in the development of certain species of Distoma. 



The Gordius varius is prolific in a very remarkable degree. A 

 female 9 inches in length, placed in a tumbler of water September 

 25, up to the present time has extruded a .string of ova 49 inches in 

 length, and still actively continues the process. 



[September, 1851. No. 86. See Bibliography.] 



Dr. Leidy further stated as follows : 



The female Gordius which he had mentioned at the last evening 

 as having extruded from September 25 up to that time a cord of 

 ova 49 inches in length had continued the process until Sunday 

 evening, October 7, up to which time it had expelled, in fragments 



* No. 57. See Bibliography. 



t Archiv. fiir Naturg., 1849, p. 358. 



* Archiv. fiir Naturg., pi. 7, fig. 10. 

 t lb., p. 374- 



