RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY. 63 



Remarks. — The more it is extended the broader and thinner it 

 becomes, especially posteriorly. When free in water, it swims like 

 the eels, and in such cases, the broad surfaces of the body are more 

 or less vertical. 



9. Meckclia Rosea, n. s. 



Body bright flesh-colored with fainter lateral margins, and a cen- 

 tral darker line inferiorily ; in transverse section oblong, convex 

 superiorly, flattened inferiorly ; when elongated, becomes cylindroid ; 

 posteriorly, obtuse. Head compressed, conical, or hastate, whitish. 

 Generative aperture distinct, round. 



Length 2 to 6 inches ; ordinarily about 5 inches. 



Habitation. — With the preceding species. 



Remarks. — As it elongates it approaches more the cylindrical form, 

 becoming thicker and narrower. 



[September, 1851. No. 84. See Bibliography.] 



OBSERVATIONS ON THE NATURAL HISTORY OF THE FAMILY OF 

 GORDIACE/E, SIEBOLD. 



Our most common species has been confounded with the Gordius 

 aqiiaticus, L. , of Europe, but a striking character at onces proves it 

 to be di.stinct. The caudal extremity of the female is trifurcated, 

 while that of the European species is blunt.* The length is from 4 

 to 12 inches. Of this species there are several varieties from differ- 

 ent localities, which may upon further comparison prove to be dis- 

 tinct species. 



To this species the name (lordius variiis w'as proposed. 



A second species of Gordius was obtained by Professor Baird from 

 a spring in Essex county. New York. It is very much more delicate 

 than the former, and from 5 to 7 inches long. The female caudal 

 extremity is blunt. The male caudal extremit}^ is bifurcate and 

 fringed with peculiar epidermoid appendages. 



For this .second species the name Gordius lineatus was proposed. 

 Dr. E. also found several remarkable species of Jlfervtis, Dujardin. 



Eleven specimens of one species were procured by Dr. Budd from 

 a ditch in New Jersey'. These are yellowish white in color, and from 

 6 to 18 inches in length. To the species the name Mermis elongata 

 was given. 



A second species was found in a ditch near Philadelphia. It is 

 pure white in color, 8 inches long, and has a peculiar tubercular 



*Siebold : Archiv. fiir Naturg., 1838, p. 303. 



