I5() [February, 



C iinditlata. Subovate, inequilateral, very thin and fragile, with obliquely 

 concentric undulations, profound on the anterior side, and suddenly becoming 

 obsolete towards the posterior extremity, which is truncated and direct; posterior 

 slope of the deeper valve obscurely tricarinated ; cartilage pit robust; valves 

 with minute, very closely arranged, granulated radiating lines. 12-10: 1 

 nearly. 



Family Pholadida. 



Pholadopsis, Con. 



Inequivalved ; right valve produced posteriorly, left valve overlapping the 

 opposite ; cartilage situated on a projecting callus. 



P. ■pectinata. Ovate, very thin and fragile, profoundly gaping posteriorly; 

 profoundly ventricose anteriorly ; valves with elevated waved laminae terminating 

 near a profound sinus, which extends from beak to base ; right valve undulated 

 near the posterior end, reflected, margin pectinated ; both valves have concentric 

 lines. 



Parapholas, Con. 



P. bisitlcata. Ovate-oblong ; anterior accessory valves or deposit strong, 

 shining, gibbous on the margin of aperture, and having obscure decussated striae, 

 the transverse ones a little raised; anterior side of the larger valves with nume- 

 rous prominent crenulated radii; a slightly oblique sulcus extends from beak to 

 base, and a slightly impressed line runs from the beak to the posterior end of the 

 closed portion of the base ; between the two impressed transverse lines the valves 

 have closely-arranged, rugose, longitudinal laminae, and posterior to these the 

 lamina; are remote and elevated. 2^. 



Penitella. 



P. Wilsonii. Ovate-oblong, very thin, profoundly ventricose ; valves with a 

 furrow from beak to base ; the papyraceous anterior valves very wide ; anterior 

 valves with numerous oblique waved laminrr, and radiating acute ribs; ligament 

 margin sinuous; posterior side with concentric distant undulations ; two small 

 accessory valves behind the beak, which are reflected posteriorly; membrana- 

 ceous appendage with a sinuous or concave margin where it joins the shell, and a 

 deep annular groove anterior to the middle. 2^. 



Triton-. 



T. perforatus. Subpyriform ; volutions 5 or 6 ; ribs revolving, flattened, 

 slightly prominent, wide and narrow alternately, with narrow interstices and an 

 occasional revolving line ; angle of body whorl tuberculated ; spire scalariform, 

 the angle of each whorl with a tuberculated rib or carina; color cinereus ; epi- 

 dermis brown, rough, hairy, longitudinally ribbed; aperture wide; margin of 

 labrum sinuous above, profoundly ribbed ; ribs about half an inch long, on an 

 ochraceous submargin ; columella with white folds, and narrow, dark brown 

 interstices; beak bent, umbilicated. 3 8-10: 2J. 



Oliva. 

 O. propatnla. Ovate-oblong, slightly gibbous towards the base; colour pale 

 ochraceous, marked with a few longitudinal zigzag brown lines, and with darker 

 transverse hair-like lines, and a few spots ; rohimella patulous, deeply sulcated 

 inferiorly; deposit at the base carinated in the middle. 2J: 1 1-10. 



