164 CO^CUYLIA—DITHYRA. 37. 



Pecfunculus rostro productiore. Lister, Conch, tab. 289, fig. 125, 



and tab. 290, fig. 126. 

 Tbe young shell. Lister, Conch, tab. 295, fig. 132. 

 3Ius. nost. On the Western coasts. 



Shell an inch and a half long, and not quite so much in breadth, 

 thick, convex, narrowed towards the beaks on the cartilage side, 

 causing them to be much produced, generally of a clear polished 

 white color, sometimes yellowish or with a tlesh-color tinge 

 towards the narrowed end, very rarely marked with broad longi- 

 tudinal fawn-colored stripes, as represented in our plate : beaks 

 curved, with a broad areola under them; inside white, glossy 

 round the margin. 



We have specimens from Panama, which in every respect 

 correspond with those of our own coasts, but are about double 

 the size. 



Tigerina. CvTHEREA testd suhorbiculari depressd, striis deeussatis, areola 

 subirigond minutd. 

 Shell somewhat orbicular and flattish, with decussate striae, and 

 the areola somewhat triangular and minute. 

 Tab. nost. 10, fig. 12. 

 Venus Tigerina. Linn. Syst. Nat. p. 1133, 1134. 

 Gmelin, Syst, p. 3283. 

 Turion, Linn. Syst. iv. p. 231. 

 Montagu, Test. p. 119, tab. 4, fig. 1. 

 Pennant, Brit. Zool. iv. p. 208. 

 Linn. Trans, viii. p. 86, tab. 2, fig. 5. 

 Turton, British Fauna, p. 158, 



