48 NOMENCLATURE. 



edeniula. Toothless 3 the margin entire. 



hians. Gaping ; the valves so partially closing, 

 that the margins do not every where touch 

 each other. 



inflexa. Inflex ; bent towards the anterior slope. 



linguiformis, Linguiform; tongue-shaped^ linear 

 with the extremities obtusely rounded. 



navicularis. Navicular; possessing the figure of 

 a boat. 



pectinata. Pectinate ; longitudinally sulcate or 

 striate; the striai forming an acute angle 

 in the anterior part. 



radiata. Radiate; with diverging rays flowing 

 from the apex longitudinally to the cir- 

 cumference. 



rostfata. Rostrated; the anterior extremity 



elongated and narrowed. 

 fastigiata. Fastigiate; leaving off transversely 

 at the base. 



saccata* Saccate 3 gibbous towards the sum- 

 mit. 



tnmcata. Truncate ; part of the circumference 

 being abrupt, or, as it were, cut off. 



