CONCHACEA. MOLLUSC A. VENUS. 85 



and it has also been taken with the dredge by Drs. Mighels and 

 Wood of Portland, in the harbour of that place. 



Mr. Say knew it only as a fossil, in which state it occurs in trfe 

 tertiary formation of Maryland. 



This is by no means an attractive shell, its dead-white surface lead- 

 ing one to suppose it to be some beach-worn specimen of Cyprina, or 

 perhaps of Venus mercendria. It is, however, much longer than the 

 former, and somewhat longer than the latter ; and it never attains to 

 any thing like the size of either of them. 



GENUS VENUS, Lm. 



Shell inequilateral, sub-ovate ; hinge with three diverging car- 

 dinal teeth in each valve ; palleal impression with a sinus. 



VENUS MERCENARIA. 



Shell solid, obliquely ovate., very inequilateral ; lunule heart- 

 shaped ; surface antiquated, bluish-white, with numerous, concen- 

 tric, laminated ridges ; inner margin broadly edged with violet. 



FIGURE 52. 



State Coll., No. 197. Soc. Cab., No. 1859. 



Venus mercenaria, LIN. ; Syst. JVaf., 1131. GMELIN: Syst., 3231. LISTER; 

 Conch., t. 271, f. 107. CHEMN. ; Conch., x. t. 171, f. 1659, 1660. DESHAYES ; 

 Encyc.Meth., Vers., iii. 117, pi. 263. LAM.; .fln. sans Vert., vi. 346, pi. 263, 

 f. 1 to 3. DILLWYN ; Cqtal., i. 176. WOOD ; Index, pi. 7, f. 40. 



Shell large, thick and solid, obliquely ovate, or heart-shaped, 

 tumid ; exterior a dirty-white and chalky ; the beaks are placed 

 far forwards, projecting nearly to the front of the shell ; they are 

 elevated, and curved so as to make nearly half a turn forwards 

 and inwards ; in front of them is a heart-shaped, rough lunule, 

 bounded by an impressed line ; behind the beaks the edge is very 

 broad and obtuse, the ligament large and protuberant, with a space 

 around it somewhat excavated, smoother than the rest, and bound- 

 ed by an obtuse ridge ; anterior end very short, round ; posterior 

 end terminating in a blunt, occasionally truncated point ; looking 

 at the side of the shell as it stands on this point, it is accurately 

 heart-shaped ; surface with concentric grooves and ridges, the 



