66 QSBORN. [Vol. II. 



the oviduct, is its histological structure, which closely resem- 

 bles that indicated by Stafford for Aspidogaster. 



Systematic Position. 



The question of the systematic position of the Chautauqua 

 Platyaspis does not at present admit of a final answer. There 

 can be no doubt of its generic position. Its anatomy agrees so 

 completely with P. lenoiri in all essential particulars, and is so 

 completely unlike that of the other genera of the Aspidoboth- 

 ridae in all generic points, that it can, I think, be finally stated 

 that it is a species of Platyaspis. 



The only divergences thus far recognized from Poirier's spe- 

 cies P. lenoiri are in the number of the compartments of the 

 ventral sucker and in the presence of eyes. As for the first 

 of these, it would be necessary to study the case of the Ameri- 

 can species more fully to determine whether the number of 

 compartments is a constant feature ; so far as is at present 

 known it is constant. And it would be necessary to study the 

 African species as well, to determine whether the account of 

 Poirier is to be regarded as absolutely and exactly true and 

 invariable. If such should prove to be the case, it would fur- 

 nish good grounds for regarding the American form as specific- 

 ally distinct. As for the point about the presence of the eyes 

 in one case and their absence in the other, it is possible that 

 the organs are not functional eyes, but only rudiments, which 

 are more distinct in the American form than in the African. 

 They may be present in the African form, but less distinct, 

 and so may have escaped notice. At all events, it is at pres- 

 ent impossible to decide that the animals are specifically dis- 

 tinct. Still, since they are so widely apart in home and habit, 

 at least so far as our present knowledge of them goes, it appears, 

 on the whole, best to recognize them by distinct names. 



