224 CONCHYLIX—DITHYRA. 49. 



cover nearly the whole surface, and are clothed with numerous 

 concave scales : the top flat, and running in a nearly straight line 

 down the open side, whence it slopes to a slightly curved point. 



papyracea. Pinna testd ovato-trigond corned, costis 9 remotis muticis. 

 Shell oval triangular horn-color, with 9 remote unarmed ribs. 



Tab. nost. 20, fig. 3. 

 Pinna papyracea. Chemnitz, viii. p. 243, tab. 93, fig. 786. 



Dillwyn, Descript. Catal. p. 381. 

 Mus. nost. Dredged off Torbay. 



Shell lour inches and a half long, and two and a quarter wide, 

 thin, brittle, horn-color, purplish towards the pointed end, and 

 marked with a blotch of the same color about the middle of the 

 cartilage side ; with 9 remote broad rounded and prominent ribs 

 which cover nearly the whole surface : the broader end nearly 

 flat, but rounded at the open side ; the pointed end runs quite 

 straight and without incurvation. 



The Pinna vitrea of Chemnitz, p, 216, tab. 87, fig. 772, is a 

 very good representation of the shell, and is probably the same 

 in a younger and more delicate state. 



miiiicata. PiNNA testd trigoiid cameold, costis 7 concapo-spinosis. 



5, 



Shell triangular pale carnation, with 7 ribs armed with concave 



spines. 

 Pinna muricata. Montagu, p. 183, tab. 5, fig. 3. 



Linn. Trans, viii, p. 113. 



Turton, British Fauna, p. 165. 



Pennant, Brit. Zool. iv. p. 244. 



