96 JOURNAL OF THE NEW JERSEY 



lage in a small pit of the hinge. White, under a very thin, 

 straw-colored epidermis. L. 5 ; H. 4 ; W. 2J ; U. f . — New Eng- 

 land. Rare. 



2. Cryptodon, Tur. 



Shell globular, with a gonial groove ; umbones much recurved ; 

 lunule short or indistinct; ligament in a groove; no cardinal teeth. 



Animal without siphonal tubes ; foot long and very slender. 



1. Cryptodon Gonldii, Phil. Shell orbicular-globose; hind 

 margin indented by a groove extending from the umbones, 

 which are small and projecting ; lunule rounded ; hinge almost 

 toothless ; surface smooth. Dead-white ; interior glossy-white, 

 with minute, radiating lines. L. 4 ; H. 5 ; W. 2J ; U. -|. — New 

 England. Rarely thrown on the beach. 



Family 13. LUCINID/E. 



Shell orbicular, white ; umbones depressed ; lunule distinct ; 

 cardinal teeth about two in each valve; ligament in a deep 

 groove or almost internal. 



1. LuciNA, Brug. 



Shell orbicular, umbones depressed; lunule distinct; ligament 

 oblique, semi-internal. 



Animal" with the mantle freely open below; siphonal openings 

 simple ; gills single on each side ; foot cylindrical, pointed. 



1. Lucina jilosa, Stim. Shell thick, regularly convex ; hinge 

 line straight ; umbones small ; lunule small, lanceolate ; surface 

 covered with numerous, remote, concentric, laminated ridges. 

 Color white or light-brown ; interior chalky-white in centre, and 

 polished at the margin. L. 35 ; H. 35; W. 15 ; U. about central. 

 — New England. Rare ; thrown on the beach by storms. 



2. Lucina (Divaricella) dentata, Wood. Shell rather thin, or- 

 bicular, regularly convex; hinge line slightly curved; lunule 

 long, lanceolate ; lines of growth quite distinct and crossed by 

 parallel ridges which extend obliquely downward toward the 

 ends from about the centre of the shell ; these ridges form about 

 a right angle where they join each other, and give the shell a 

 dentate edge. White. L. 22 ; H. 20 ; W. 12 ; U. |.— Cape Cod 

 and south. Dead shells common. 



Family 14. CARDIID/E. 

 Shell regular, equivalve, free, cordate, covered with radiating 



