103 



F. p. 398. A. PERFORANS. Turt. D. p. $.Turt. 

 B. p. 169. t. 13. /. 2,3. Oblong, subequilateral, 

 rounded posteriorly and angular anteriorly, white with 

 a brown velvety epidermis, and crowded longitudinal 

 riblets which are merely crossed by the striae of growth ; 

 beaks distant, the ligamental area black oblong and 

 sunken; inside white, ventral edge but slightly open. 

 \...\. W. Coasts, in rocks. 



GENUS. PECTUNCULUS. 

 Suborbicular, double convex, equivalve, subequilateral 



and closed; hinge arcuated, teeth numerous, oblique, 



serrated; ligament external. 



P. GLYCIMERIS. Deshayes. P. GLYCIMERIS, UN- 

 DATUS & PILOSUS. Turt. B. p. 171. t. 12./. 1,2,3,4. 

 P. P. & P. MARMORATUS. Lam. P. PILOSUS. 

 Phillippi.F. p. 400. ARC A. G. Lin.Mus. Ulric. 

 A. PILOSUS. D. p. 242. A. MARMORATA. GmeL 

 3314. Ch.f. 560. $ 563. List. t. 247. /. 82. 

 Knorr. 6. t. 14. /. 4.Gual. t. 72. f. 6.E. t. 310. 

 /. 3. A. GLYCIMERIS. Pen. 4. p. 216. Lin. T. 8. p< 

 93. t. 3./. 3. Turt. D. p. 7. Orbicular-ovate, be- 

 coming inequilateral by age, white with angular red 

 streaks arranged either longitudinally or transversely 

 (sometimes flesh-coloured with white spots and angular 

 red ones), minutely decussated, the apices obliquely 



