116 GOIUGBYUA—DITHYRA. 28. 



Shell more than an inch in diameter, very thin and brittle, yellow- 

 ish white, irregularly striate transversely, a little undulate in the 

 circumference : beaks nearly central, without impression under them, 

 inside glossy yellowish-white : hinge with three teeth in one valve, 

 the middle one cloven. 



Radula. LuciNA testd lentiformi, strus transversis crebris laminatis, valvis 

 bidentatis. 

 Shell lenticular, with close-set transverse laminar striae, and two 



teeth in each valve. 

 Tellina Kadula. Montagu, Test. Brit. p. 68. tab. 2, fig. 1, 2. 

 Linn. Trans, viii. p. 54. 

 Pennant, Brit. Zool. iv. p. 181. 

 Turton, British Fauna, p. 151. 

 Wood, Conch, p. 183. tab. 42, fig. 4, 5. 

 Turton, Conch. Diet. p. 175. 

 Venus borealis. Donovan, British Shells, iv. tab. 130. 

 Venus spuria. Dillwyn, Descript. Catal. p. 194. 



Cognata Veneris Pensylvanicae. Chemnitz, vii. p. 16, tab. 38, fig. 



399. 

 Pectunculus subfuscus. Lister, Conch, tab. 293, fig. 129. 

 Mus. nost. Western and Irish coasts. 



Shell an inch and a half in diameter, rather convex, running in a 

 straight line on each side the beaks, giving that end of the shell a 

 rather truncated appearance, white or covered with a pale brown skin 

 and marked with numerous rough raised concentric ridges: inside 

 dull chalky white, except round the area of the margin, which is po- 

 lished and furnished with longitudinal lines, as in many species of 



