288 New Species of Corhula from Jamaica. 



inequivalvi, vix inequilaterali, posticS acuminata, margine ven- 

 tral! excurvata: albidil': rugis irregularibus parvis concentricis, 

 in lunulam liaud productis, ad valvam magnam hand multum 

 majoribus; junioribus exilissim^ radiatim striatis: apicibus 

 parvis, baud involutis : umbonibus postice acut5 angulatis : den- 

 tibus parvis. Long. 8"'.9 ; alt. 5"'.2 ; lat. 4"'.3. 



Shell ovate-triangular, somewhat thin, inequivalve, slightly 

 inequilateral, posteriorly acuminate, with the ventral margin 

 well rounded : whitish : with small concentric irregular ridges, 

 which are a little larger on the large valve, not produced into 

 the lunule ; with minute radiating striae in young shells : beaks 

 small, not involute : umbones with an acute angle posteriorly : 

 teeth moderately developed. 



Length .35 inch ; breadth .26 inch ; height .17 inch. 



Station. — In mud, in 4 or 5 fathoins water ; C. B. A. ! 



Habitat. — Kingston harbor, Jamaica ; C. B. A. ! About 200 

 specimens were collected, many of which are immature. 



COKBULA Chittyana.' — C. t. Barrattiance simili ; sed multiim 

 crassiore, latiore, inequivalviore ; prsecipue differt quoad cres- 

 cendi rationem duplieem, sieut C. Dietziana. Long. 8"'.6 ; alt. 

 5'".8; lat. 5"'.2. 



This species resembles C. Barrattiana, but differs in being 

 very thick and solid, very wide, and in having two periods of 

 growth, like C. Dietziana : it is also more inequivalve. 



Length .34 inch; height .23 inch; breadth .22 inch. 



Station. — In 4 or 5 fathoms water, in a muddy bottom ; C. 

 B. A.! 



Habitat. — Kingston harbor, Jamaica ; C. B. A. ! We obtained 

 only 4 specimens of this rare shell. 



CoRBULA Knoxiana. C. t. ovato-rhombica, subcrassa, sub- 

 equivalvi, vix inequilaterali, postic6 truncata et infra acuminata ; 

 margine ventrali recta vel baud multum excurvata: albida: 

 rugis concentricis reclivatis acutis regularibus, in speciminibus 



