1887.] NATURAL SCIENCES OF PHILADELPHIA. 33 



small, mainly internal; free margins apparently smooth; pallial 

 line apparently simple. 



This genus agrees with Crassatella in having both lunule and 

 escutcheon clearly defined, in the general character of the hinge, 

 exclusive of the lateral teeth, in the nearly internal position of 

 the ligament, and, apparently, in having a simple pallial line. It 

 differs from Crassatella in its small and compressed beaks, the 

 laterally compressed form of the shell, in its greater number of 

 cardinal teeth; and in the long and slender character of both 

 the anterior and posterior lateral teeth. 



It agrees with Astarte in having both lunule and escutcheon 

 well defined; but it differs from that genus in having a greater 

 number of cardinal teeth; in its well developed anterior and 

 posterior lateral teeth ; and in having its ligament mainly internal. 



It agrees with Circe (as represented by C. scripta, Lin.) in 

 its laterally compressed form, especially that of the umbonal 

 region, and in the number of its cardinal teeth. It diflfers from 

 Circe in having its ligament mainly internal; in the long and 

 slender character of the anterior lateral teeth, and in the posses- 

 sion of posterior lateral teeth. 



It agrees with Eryjihila in having both lunule and escutcheon 

 well defined, and, approximately, in the character of its posterior 

 and anterior lateral teeth. It diflfers from that genus in having 

 a greater number of cardinal teeth, and in having its ligament 

 mainly internal. 



It has somewhat the aspect of Gouldia, but it differs from that 

 genus in having slender, well developed posterior, as well as 

 anterior lateral teeth. It has also a greater number of cardinal 

 teeth than Gouldia and its ligament is differently situated and 

 partly external. 



The only species of this genus which I have satisfactorily 

 examined is the one which is described in the following paragraph. 

 This I regard as the type of the genus, but it is likely that the 

 Astarte carinata of d'Orbigny^ is congeneric with it. 

 Stearnsia Robinsi (sp. nov.) Pi. II, figs, 79. 



Shell much compressed, trihedral in marginal outline; lunule 

 long and narrow, nearly straight from end to end, concave trans- 

 versely; escutcheon similar in shape and character to the lunule, 

 but longer; beaks small, appressed, angular; ligament slightly 



1 See Pa4cont. Francaise, Ter. Cret. iii, pi. 262, figs. 1. and 2. 



