124 Dentition of Pulmonate Mollusks. 



Leptomerns sepulcralis, Poey. New Providence, Bahamas. 



Jaw stout, wide, low, arcuate, of about equal height throughout, ends 

 bluntly rounded; anterior surface with 15 stout, broad, crowded ribs, their 

 ends crenulating either margin ; some of these ribs are of equal thickness 

 throughout, and are separated by decided, narrow interstices; the jaw can- 

 not, therefore, be said to resemble that usual in Bulimulus, though it seems 

 to combine some of the characters of that and of the simply ribbed form 

 of jaw. 



Lingual membrane as in B. chrysalis; no side cutting points to centrals 

 and inner laterals. (PI. XI, fig. J.) 



Leptomerus corneas. Nicaragua. Mr. McNiel. 



Jaw as in Bulimulus ; 15 ribs. 

 Lingual membrane as in B. chrysalis. 



RMnus durus, Spix. Brazil. J. G. Anthony. 



Jaw as usual in Bulimulus. 



Lingual membrane as in B. chrysalis. 



Plectostylus Peruvianas. Brug. Talcahuana, Pern. 



Jaw as usual in Bulimulus ; 30 ribs. 



Lingual membrane (PI. XII, fig. J) combining the characters of that of 

 B. memhranaceus in the marginals with those of B. chrysalis in the centrals 

 and the five laterals on both sides of the median line ; the cusp of the last 

 is large, oblique, rounded. 



Bulimulus Edivardsi, XTor. Lake Titicaca. Prof. Alex. 

 Agassiz. 



Jaw low, arcuate, ends rapidly acuminated, blunt ; anterior surface 

 with over ten distant ribs, some of the usual Helix type, others like the 

 delicate ribs common in Cylindrdla, Bulimulus, Gceoiis. Amphibulima, etc. 



Lingual membrane (PI. XI, fig. K) with 44-1-44 teeth. Centrals of the 

 usual Helicince type, tricuspid ; laterals like centrals, asymmetrical, and 

 consequently bicuspid. The change to marginals very gradual, and formed 

 by the simple modification of the laterals, without any splitting of the inner 

 cutting point. 



Subgeneric position of this species is unknown to me, as of the following. 



Bulimulus Gabbianus, Angas. Costa Pica. Dr. W. M. Gabb; 

 formerly referred to B. Irazuensis. 



Jaw as in Bui. limnceoides, but median ribs oblique ; there are about 32 

 ribs. 



Lingual membrane with marginals as in B. Bahamensis. (PI. XII, fig. L.) 



Cylindrella. 



Jaw arched, ends attenuated ; very thin, transparent ; dis- 



