182 AMERICAN JOURNAL 



Jaw long, low, slightly arcuate, thin, semitransparent, com- 

 posed of numerous plates, as in Helix turbiniformis, see Annals 

 N. Y. Lye., X, PI. ii. The membranous attachment at the upper 

 margin is very stout in this specimen, apparently of the same color, 

 consistency and material as the body of the jaw itself. 



A specimen from the Isthmus of Tehuantepec furnished the 

 jaw here described. 



Bulimulus membranaceus, Phil. (Mormus.) 



Jaw slightly arcuate, ends acuminated ; apparently in twenty- 

 four separate plates, of same character as in the last species. 



Lingual membrane unsatisfactorily mounted. Teeth appar- 

 ently of same type as in the last species, the centrals, however, 

 distinctly tricuspid. 



Brazil. Collected by Mr. J. G. Anthony. 

 Bulimulus Jonari, Pfr. (Mormus.) 



Jaw slightly arcuate, long; ends blunt, scarcely attenuated;, 

 apparently composed of numerous separate plates, as in the last 

 species. 



Lingual membrane unsatisfactorily mounted, the teeth, how- 

 ever, appear of the same type as those of B. aureolus, above. 



Bulimulus dealbatus, Say. (Scutalus.) 



A jaw of this species lately received differs somewhat from 

 the one figured in Land and Freshwater Shells, I, p. 209. It 

 is not strongly arcuate, but only slightly so. It has but ten 

 ribs, quite broad, on the anterior surface, crenellating either 

 margin. The jaw is quite thin, of a light horn color. 



Bulimulus Berendti, Pfr. ? 



Jaw slightly arcuate, long, low, ends slightly attenuated, appa- 

 rently composed of fifteen separate plates, or folds, as in B. 

 alternates, above. 



Lingual membrane long and narrow, composed of numerous 

 rows of teeth. Centrals and laterals as usual in the genus, mar- 

 ginals irregularly denticulated or serrated. 



Nicaragua. Mr. McNiel. 



This species has not been determined, but is closely allied to 

 B. Berendti, Pfr. 



Bulimulus durus, Spix. (Rhinus.) 



Jaw long, slightly arcuate, low, ends but little attenuated ; 

 apparently composed of numerous separate plates, or folds, as in 

 B. altei'natus, above. 



Lingual membrane with teeth as usual in the genus. Centrals 



