CORBULIDAE 91 



occasional growth bands near border. 



Corbula caribaeai^o d'Orbigny PI. 18, fig. 119 



Alt., 4.5; length, 8.5; diam., 4.5 mm. Adult shells inflated, 

 juvenile often compressed; right valve margin projects beyond and 

 almost encloses left valve, especially toward posterior end; umbos 

 incurved; posterior extremity prolonged and pointed. A slightly flat- 

 tened area anterior to umbos; posterior rostrum at right angle with 

 plane of valves, oval when viewed from above. A few fine radiating 

 striations, concentric ribs less well marked over posterior slope. Base 

 rather flattened, almost without sculpture. 



From four to six fathoms. 



f orl)ula cubanianai^i d'Orbigny PI. 44, fig. 310 



Alt., 4.75; length, 8.5; diam., 3 mm. Shell with pink epaulettes 

 radiating from umbos, some specimens entirely pink. Almost equi- 

 valve, right valve a little deeper and its umbo a little higher than 

 left valve, margin slightly overlapping. Posterior rostration pointed 

 at base. 



From three to six fathoms. 



Corbula krebsiaiui C. B. Adams PI. 18, fig. 120 



Alt., 5.1; length, 6.1; diam., 3.5 mm. Shell decidedly trigonal 

 and extremely inequivalve; right valve sharply rostrate; umbos 

 rounded; inflated; closely ribbed. 



From four to seven fathoms. 



Corbula swlftiana C. B. Adams PI. 18, fig. 121 



Alt., 5.5; length, 9; diam., 4.5 mm. Shell almost equilateral; 

 right valve deeper and a little longer; overlapping of margin most 

 marked in young shells; posterior rostration sharply marked, the 

 flat area of each valve in same plane; umbos sharp; umbos and an- 

 terior and posterior radial ridges opaque milky white; faint radiate 

 striations. Egg capsules of some small gasteropod are often seen on 

 the posterior extremity of these shells, and the shells are often bored 

 near umbos. 



From less than one to six fathoms. 



^^^ Caribbean. 

 161 Of Cuba. 



