344 Lingual Dentition and Anatomy of 



are described as having a jaw with nine decided ribs* dcntic- 

 iilating the cutting edge and teeth of the usual form of the 

 Helicihm — quite different from our appendiculata, which is, 

 we believe, distinct from his species. 



Pellicida convexa, Martens (Succinea) , belongs to the genus 

 Omaloni/x, as shown by Heynemann's figure of the jaw 

 (Malak. Blatt., XV). 



AmpliiOdiiliiiia^ I>Rtii!s», Brug. 



We have elsewhere described the lingual membrane of this 

 species from a Dominica specimen (Am. Journ. Conch., 

 VII, 18t), pi. xvii, f. 1, 2,) and the jaw of one from St. 

 Kitts (Ann. Lye. N. H. N. Y., X, 225^ pi. xi, f. 8). 



It has lately been suggested by Schramm (Journ. de Conch., 

 XIII, 127, April, 1873) that this s[)ecies belongs exclusively 

 to the fiiuna of Guadeloupe, and does not exist in the neigh- 

 boring islands. We have seen one fossil example only from 

 Guadeloupe, but on comparing it with fresh specimens from 

 St. Kitts and Dominica are satisfied, judging from the shells, 

 that all are of one and the same species. 



Considering Schramm's views, we have again carefully ex- 

 amined the lingual membranes already described of the St. 

 Kitts and Dominica forms, to ascertain whether they present 

 differences of specific value. It ma}- be mentioned that the 

 shells from the latter island, several of which are in the 

 cabinet of the late Mr. Robert Swift, are smaller than those 

 from St. Kitts. 



We find that the Dominica form has sharper cutting points 

 to the large cusps of its central and lateral teeth than in the 

 St. Kitts' examples, while the laterals of the latter show 

 greater constancy in the square truncation of the cutting- 

 points. 



The teeth of the St. Kitts lingu:ds arc broader in propor- 

 tion to their length, have a greater curve in their outlines and 



* In Fischer's plate the references to the teeth of Omulunyx unguis and Peilkula 

 depressa are reversed. 



