l74 AMERICAN JOURNAL 



NOTES ON THE LINGUAL DENTITION AND JATATS OF TER- 

 RESTRIAL MOLLUSCA. NO. 3. 



BY THOMAS BLAND AND W. Q. BINNEY. 



In the following pages we have not considered it necessary to 

 describe fully the lingual dentition of those species which agree 

 with the usual type of dentition in their respective genera. In 

 the Helicidce we have given more particular notes on the mar- 

 ginal teeth, because they are not so constant in their characters 

 as the central and lateral teeth. 



ZONITES CAPSELLA, Gould. 



Lingual membrane broad, not very long. Teeth as in the 

 species of Hyalina figured by us in Land and Fresh-water Shells, 

 Part 1. The laterals and centrals are about equal in size, the 

 former very few in number, apparently three only. Marginals 

 numerous, large, decreasing in size as they pass off laterally, 

 and quite separated near the outer margin of the membrane. 



Specimen from Lexington, W. Virginia, received from Pro- 

 fessor McDonald. 



ZONITES LIGERUS, Say. 



Lingual membrane as usual in the genus Hyalina. The cen- 

 tral teeth are small in proportion to the laterals. 



Jaw already figured by Leidy (Terr. Moll. U. S. L, pi. XII. 

 fig. 7.) 



ZONITES GULARIS, Say. 



Jaw highly arcuate, ends attenuated, anterior surface smooth, 

 cutting edge with a well developed median projection. 



The lingual membrane has been described by us on p. 293 of 

 Land and Fr. W. Shells, Part I. 



