﻿155 Florida Oligocene Shells 37 



margin of the shell. Length of largest specimen (imperfect) 9 ; 

 altitude 6 mm ; length of younger specimen (complete) drawn 6 ; 

 altitude 4 mm. 



Chipola marls, Bailey's Ferry, Florida. 



Cornell University collection. 



Pitaria (La»iellico?icha) Harrisi, n. s. 

 PI. IX, fig. 7. 



Shell nearly orbicular, slightly compressed and inequilateral, 

 with regular, close, concentric ribs ; beaks not prominent ; lunule 

 rather small, well-defined, cordate ; anterior end rounded ; 

 posterior bluntly angulated ; base either rounded or in some 

 specimens slightly angulated ; hinge strong, the anterior laterals 

 and the cardinals well developed ; pallial sinus deep, ascending, 

 triangular, reaching to the middle of the shell. Length of 

 largest specimen 16.5 ; height 15 ; diameter of one valve 3 mm. 

 The usual size is, however, much smaller. 



This species resembles in general form and sculpture P. imi- 

 tabilis Conrad, but the shell is smaller and the ribbing closer. 



Chipola marls, Bailey's Ferry, Florida. 



Cornell University collection. 



Sonde perlamelloides, n. s. 

 PI. IX, fig. 8. 



Shell thin, oval-orbicular, equilateral ; beaks low, very 

 acute ; dentition and interior of shell concealed by the matrix ; 

 surface with close-set, regular, raised concentric lamellae ; slightly 

 angulated on the posterior slope. Length 38 ; height 30 ; di- 

 ameter 12 mm. 



This shell resembles closely S. perldmellosa Heilprin from 

 the Pliocene of the Caloosahatchie, but is proportionally shorter 

 and higher than that species of which it is no doubt the ancestral 

 form. 



Chipola marls, Bailey's Ferry, Florida. 



Cornell University collection. 



