NOMENCLATURE, 25 



BIFALVES, 



Ambitus. Circumference of the shell. 



Area. Slope. 



antica. Anterior slope or Area ; that side of the 



beaks or that space in which the ligament 



is situated. 

 dhtincta. Distinct j separated from the sides of 



the shell either by a channel or a keel. 

 ipflexa. Inflex; having incurved lips. 

 literata. Literate ; ornamented with characters 



like letters. 

 postica seu Areoi-a. Posterior slope ; the other 



side of the beaks. 

 marginata. Marginate ; surrounded by an ele- 

 vated margin. 

 patula. Patulous; the margins of the areola 



gaping. 

 serrata. Serrate ; saw-like in the channel of the 



areola. 

 Apices. Beaks ; the tips or extreme parts of the 



umbones or bosses. 



