VENUS. 165 



This shell may be at once distinguished from V. verrucosa by 

 the posterior depression being reuiform, and in a specimen 

 now before me, which is two inches and a quarter long, the 

 transverse ribs are more membranaceous, and are not at all 

 tuberculated at either end ; the anterior slope in one valve is 

 glabrous ; colour whitish, irregularly stained, and marked 

 with spots, or short angulated streaks of pale brown. 



casina. 14. Shell somewhat heart-shaped, with 

 acute recurved transverse ribs, and grooved 

 behind the beaks ; margin crenulated at the 

 posterior end. 



Venus Casina. Linn&us Syst. Nat. p. 1130.? Chemnitz, 

 vi. p. 306. t. 29- f. 301 and 302. Schroeter Einl. iii. 

 p. 115. t. 8. f. 6. Gmelin, p. 3269- Maton and Rack- 

 et, in Lin. Trans, viii. p. 79- t. 2. f. 1. Montagu Supp. 

 p. 47. 

 Venus erycina, worn shell. Pennant Zool. iv. p. 94. t. 54. 



f. 48. A. 

 Venus lactea. Donovan, v. t. 149. Maton and Racket, 

 in Lin Trans, viii. p. 79. Montagu Supp. p. 46. 

 Inhabits the European Ocean. Linnaus. Coasts of Britain. 



Pennant, fyc. 

 The description in the Systema Naturae is so short, and unac- 

 companied by any reference, that the Linnaean V. Casina 

 must always remain an uncertain species, and it appears 

 from his MSS., that Dr. Solander considered it to be our 

 V. Gallina. The shell here referred to, which answers the 

 Linnaean character much better, is said to be about an inch 

 and a half in diameter, thick, white, and variegated with 

 brown, but whether it is more than a variety of V. rigida is 

 rather doubtful, and in that species the posterior depression 

 is surrounded by a groove. 



cancellata. 15. Shell somewhat heart-shaped, 

 with longitudinal striae, and transverse re- 

 mote membranaceous ribs ; posterior depres- 

 sion heart-shaped. 



Venus canceilata. Limucus Syst. Nat. p. 1130. Chemnitz, 

 vi. p. 309. t. 29. f. 304 to 307. Schroeter Einl. iii. p. 

 116. Gmelin, p. 3270. Donovan, iv. t. 115. Mon- 

 tagu Test. p. 574. 



Venus laminosa. Montagu Supp. p. 38. ? 



