Cotylogaster occidentalis n. sp. Q\^ 



Concerning the internal structure of the Single specimen representing 

 this genus its systematic position will continue a matter of conjec- 

 ture. In view hovvever of Diesing's Statement (in: Ann. Wien. Mus., 

 V. 2, 1839, p. 234) quoted by Monticelli, that the animal has a 

 forked intestine I fully agree with Braun that it should not be classed 

 among the Aspidohothridae. 



The genus Flatyaspis Mont. I have also suppressed putting the 

 form for whose receptiou Monticelli established this genus in the 

 genus Cotylaspis; hence the names Aspidogaster lenoiri Pom. and 

 Flatyaspis lenoiri Mont. become Synonyms of Cotylaspis lenoiri. 

 KoFOiD ('99) while producing conclusive evidence of the vahdity of 

 Leidy's genus Cotylaspis holds nevertheless that "Monticelli's genus 

 Flatyaspis should for the present at least be retained for the re- 

 ception of Poirier's species". As in suppressing Monticelli's genus 

 Flatyaspis I have acted in accordance with a conflicting opinion I 

 will State here some of my reasons for doing so. Kofoid says: "The 

 points of contrast between the two genera {Cotylaspis and Flatyaspis) 

 as described are the presence or abseuce of eyes, the number of al- 

 veoli in the ventral sucker (29 in Cotylaspis., 25 in Flatyaspis) and 

 the ectoparasitic habit of the one and the endoparasitic habit of the 

 other". I am uuwilling to concede that either of these three dif- 

 ferences is of generic importance. Osborn's Observation that some 

 specimens of Cotylaspis insignis are destitute of eyes together with 

 the fact mentioued by Kofoid that "the absence of eyes in Flaty- 

 aspis is inferred froni Poirier's silence upon the subject" make the 

 first ditiereuce of very slight value, certainly too small to be made 

 the basis of generic distinction. I regard it as deserving no greater 

 consideration thau the presence or absence of marginal sense organs 

 which we know are present in C. insignis but know nothing about in 

 C. lenoiri since "Poirier in his original description makes no State- 

 ment as to the presence or absence of these organs" (Kofoid). 

 Kofoid evidently does not consider this (possible) ditference as de- 

 serving any consideration since he falls to mention it as one of the 

 "points of contrast between the two genera". I quite agree with him 

 that Poirier's failure to mention them is no better evidence against 

 their presence than was Leidy's failure to mention them in C. in- 

 signis in which form we now know that they are present. I regard 

 their presence in C. lenoiri extremely probable. 



If a ditference in the number of alveoli in the ventral sucker be 

 considered a generic distinction every species now included in the 



