122 GOiaCBYLlA—DITHYRA. 31. 



Turton, onch. Diet. p. 177. 

 Venus sinuosa. Donovan, British Shells, ii. tab. 42, fig. 2. 

 Mus. nost. From the Western coasts, and Ireland. 



Shell hardly half an inch in diameter, somewhat orbicular but 

 produced at the hinge, very convex, thin, white, transparent, finely 

 but irregularly striate transversely: from the beaks, on the anterior 

 side, runs a longitudinal furrow which forms a Hexure at the margin, 

 and a prominent angle half way towards the hinge : beaks promi- 

 nent, slightly curved, with a small heart-shaped impression under 

 them on the side opposite to the flexure : teeth extremely minute, 

 and so obscure as hardly to be distinguished by a very considerable 

 magnifying power. 



31. DONAX— L/iVNE. 



Testa transversa, cequivalvis, inoequilateralis ; latere antico obtuso, bre- 



vissimo. Cardo dentibus duobus : lateralibus remotiusculis. Liga- 



mentum externum, ad latus brevius. 

 Shell transverse, equivalve, inequilateral; with the anterior side 



obtuse and very short. Hinge with two teeth in both valves ; 



lateral teeth rather remote. Ligament external, at the shorter 



side. 



