No. 4-] IDENTITY OF COTYLASPIS. l8l 



to tell, " within the cleft of the upper branchial cavity, adhering 

 to the outer surface of the renal organ and the continuous 

 margin of the foot." The next year Dr. Leidy ('58) published 

 the following more extended diagnosis of this new genus and 

 species, allied to Aspidogaster : 



Cotylaspis Leidy. — Body curved infundibuliform, anteriorly cylindro- 

 conical, posteriorly expanding into a subcircular or oval ventral disc with 

 numerous acetabula arranged in a triple series. Mouth infero-terminal, with 

 a prominent upper lip, and protractile into a cup- or disc-like acetabulum. 

 Intestinal apparatus as in Aspidogaster. Eyes two, distinct, black, situated 

 on each side of the head. Generative apertures inferior, between the head 

 and ventral disc. 



Cotylaspis insignis Leidy, Proc. Nat. Sci., 1857, 18. — Translucent white 

 or pink white. Upper lip snout-like, conical. Ventral disc crenate at the 

 margin ; acetabula 29, oblong quadrate, the outer rows continuous in front 

 and behind so as to form a circle. Length from ^ to i line ; ventral disc 

 from % X.O yi 2. line in diameter. 



Habitation. — Found adhering to the outer surface of the renal organ, 

 and the upper margin of the foot, within the cleft of the upper branchial 

 cavity of Anodonta fltiviatilis and A. lacustris. 



Remarks. — This curious parasite, though allied to Aspidogaster conchi- 

 cola, is certainly distinct ; and it never occupies the locality of the latter, 

 which also is found in the pericardium of Aiiodouta fluviatilis and A. 

 lacustris. It is an interesting fact that in accordance with its exterior posi- 

 tion Cotylaspis possesses well-developed eyes, while the imprisoned Aspido- 

 gaster is blind. It has occurred to me that perhaps these two genera may 

 represent two different stages of existence of the same animal. 



Diesing ('59), in his Revision, recognized Leidy's genus Coty- 

 laspis, associating it with Aspidogaster ; Taschenberg ('79) 

 recognized the genus, according it a position in the system 

 between Aspidogaster and Aspidocotyle ; and Hoyle ('88) also 

 accepted the genus, associating it, as Taschenberg did, with the 

 above-named genera. In 1885 Poirer described Aspidogaster 

 lenoiri from the intestine of Tetrathyra vaillantii, a turtle from 

 Senegal, but did not mention its striking similarity to Cotylaspis 

 insignis in the general form, structure of the ventral sucker, 

 and the gross anatomy which he briefly describes, Monticelli 

 ('92) established a new genus, Platyaspis, for this peculiar spe- 

 cies, but, with an interrogation point, made the closely related 

 Cotylaspis a synonym of Aspidogaster conchicola, justifying this 



