58 



auriculis sub-scqualibus ; valva sinistra ventricosa ; A^aiva 

 dextra sub-depressa, auricula antica validissime emarginata ; 

 colore corneo, fusco variegato, intiis fusco purpurascente 

 fasciato. Long. 0, 45; lat. 0, 17- alt. 0, 40. poll. 



Rounded, inequivalve, smooth, thin, nearly equilateral ; 

 the auricles nearly equal ; the upper valve ventricose ; the 

 lower valve rather depressed, with the anterior auricle 

 widely emarginated ; the colour of the upper valve is horny, 

 with a broad sulj-marginal band of purplisli dark brown, and 

 speckled withlighterbrown ; the lowervalve is much lighter, and 

 has only light brown speckles. British Museum. Co. of Africa. 



39. P. HYALixus. (pi. xiv.f. 66. 67.) Poli. t. 28. f. 6. 



T. rotundata, Iffivi, hyalina, sub-compressa ; lateribus 

 sub-expansis ; auriculis magnis, sub-ccqualibus, acutangulatis, 

 ])lanis ; colore corneo, rubro, fusco alboque radiatim maculato. 

 Variat immaculato. Long. 1 ; lat. 0, 39 ; alt. 0, 95 ; poll. 



Rounded, smooth, glassy, nearly flat, rather expanded at 

 the sides ; auricles large in proportion to the shell ; the 

 colour is red, with small angulated marks of brown and white 

 arranged in rays ; in some varieties there are no spots. 



Mediterranean. 



40. P. FLAGELLATTS. (pi. xiii. f. 4 1 to 43.) Zff7/2. Anim. 

 sans Vert. vi. p. 167. 



T. rotundata, sub-quadrata, compressa, tenui, pellucida, 

 irregulariter costata vel striata ; auriculis magnis, acutis ; 

 colore corneo, ad latera et ad auriculas roseo vel luteo, fusco 

 alljoque angulatim minute variegato, variat fusco-nigrescente. 

 Long. 0. 75.; lat. 0. 16.; alt. 0. 70.; poll. 



Of a squarish round shape, thin, nearly transparent, irregu- 

 larly ribbed or striated, that is, the striae in some varieties 

 nearly large enough to l^e called ribs ; auricles large, with 

 acute angles, the colour is horny, pinkish or yellowish at the 

 sides and auricles, with minute angular marks of white and 

 brown ; and there is also a variety of a blackish brown. 



Mediterranean. 



41. P. GLAF.EU. (pi. xviii. f. 169 to 176.) Linn, according to 

 Gmel. P. flavidulus, sulcatus, virgineus, griseus, virgo. Lam. 

 Ostrsea lutea ? fiavescens ? aurantia ? modesta ? depressa ? 

 Gmel. O. citrina, rustica, PoU. 



T. rotundata, sub-complanata, leevi vel radiatim striata ; 

 margine expanse ; auriculis sub-aequalibus, latis, acutangulatis; 

 costis decem, rotundatis, paululum elevatis, prope margines 

 evanidis, alternis miniis elevatis; colore vario. Long. 2. 10,; 

 lat. 0. 65.; alt. 2. poll. 



