ON THE ANGUILLULIDyE. 175 



cylindrical intestine; anus none(?) or exceedingly indistinct. Caudal extremity 

 obtuse. Generative aperture of the female near the middle of the body." 



P. NiTiDUM, Leidy. 



" Body cylindroid, most narrowed anteriorly. Head without appendages. Caudal ex- 

 tremity broad, obtusely conical. Length 5 lines ; breadth |th of a line." 



" An active, wriggling, glistening-white worm, found among beds of ValUsneria ameri- 

 cana growing in the river Schuylkill, near Philadelphia." 



36. NEMA, Leidy. 



Proceed, of Acad, of Philad. viii. (1856) 49. 

 Gen. Char. " Body ascaridiform. Head without appendages. Mouth unarmed, large, 

 infundibuliform ; oesophagus tubular, membranous, expanding into a simple, straight 

 intestine ; anus ventral. Tail conical, acute, recurved. Generative aperture near 

 the middle of the body." 



N. VACiLLANs, Leidy. 



" Body white, glistening. Length ll"""; breadth -050"'". Tail -115°"" long." 



" An active, wriggling worm, found about some dead specimens of a black Phryganea, 



which was infested witli a fungous parasite, and attached to stones at the water's edge of 



a small brook near Philadelphia." 



37. UROLABES, Carter. 



" The generic name of Urolabes, which I have employed, should only be viewed as 

 provisional. It has been chosen from the striking habit which all these worms have of 

 attaching themselves to some object by the tail, whether it be by embracing it or by 

 adhering to its surface. Hence the tail would appear to be both prehensile and adhesive? 

 if not suctorial. Having once fixed themselves in this way, they keep up an undulating 

 movement from the tail forwards, which, in the absence of any evident purpose, seems 

 more for respiration than anything else." — Ann. of Nat. Hist. ser. iii. vol. iv. p. 99. 



Amongst the ten species described by Carter, there are representatives of several 

 genera ; and I have been able to assign positions to three of the species — one in the 

 genus Dorylaimus, one in Chromadora, and one in Syniplocostoyna. Of the remainder, 

 three (Z7. gloeocapsarum, U. labiata, and TJ. tentactdata) seem, by the form of their 

 gesophagus, almost to belong to the genus Bhabditis, although this is somewhat nega- 

 tived by the absence of caudal alse in the male of TI. gloeocapsarum, the males of the 

 other two species not having been discovered. 



1. U. GLCEOCAPSARTJM, Carter. 



Loc. cit. p. 40, pi. iii. fig. 25. 



" Female, linear, cylindrical, striated transversely, gradually diminishing towards the 

 head, which is obtuse and without papilla3 ; also towards the tail, which is long and 

 fm'nished with a digital termination. Vulva a little anterior to the middle of the body." 



