TRIBE PECTINIDES. 295 



as almost to become obsolete in the more typical examples : interstices 

 sculptured. 2£. China. 



S. Gussoni. Costa, Tes. Sic. p. U.—Phil, 1, p. 87, t. 5, /. 16 ; 

 2, p. M.—Kust. vii. 2, t. 6,/. 3, A.— Sow. Th. 1, ^. 430, t. 89, /. 54. 

 — S. Albidus, Brod. Z. P. 1836, p. 43.— S. Minimus, <7^hm, II. C. 

 Sp. t. 24, /. 3. Small, wholly white both within and without, sub- 

 ovate, more or less compressed at the sides dorsally, scarcely eared, 

 merely radiated in both valves by very numerous narrow unarmed 

 costellae or coarse raised striae : inner margin closely and strongly 

 crenated. f. Mediterranean. The attached valve is usually gibbous. 



S. Asperrimus. Sow. Z. P. 1847; Th. 1, p. 421, t. 87, /. 38. 

 Colour (in the few specimens known) pinkish drab ; entire surface 

 most 'closely rayed with crowded costellae and elevated striae, that 

 everywhere bristle with more or less elevated small spines. None of 

 the costellae are peculiarly prominent, but each, as it is permitted to 

 develop itself, becomes squamiferous and finally aculeated. 4. U. 



S. Lingua-felis. Sow. Z. P. 1847 ; Th. 1, p. 420, t. 88, /. 50. 

 Solid, of an uniform dull orange-red, crowded with most numerous 

 (about 70) equal-sized radiating costellae, which are armed with most 

 thickly set short squamular spines ; interstices narrow and smooth. 



4. U. 1 



TEIBE OSTEACEA. 



Ligament either internal or nearly so: shell irregular in form, 

 foliaceous, or at times papyraceous. 



OSTREA. 2 



Shell affixed, ineauivalve, irregular; the beaks not touching, but 

 rather diverging, the lower one often produced ; upper valve the smaller, 

 and in growth enlarging anteriorward ; devoid of regular teeth, but 

 usually provided with denticles on either side of the hinge ; ligament 

 semi-internal, its pit increasing with age. 



* Margin not infolds, but simple or waved. 



O. Edulis. Lin. 1148.— Lam. l.—D. p. 280.—Turt. B p. 204. 

 —Mont. p. 152.— Sow. G.— Reeve, t. 120,/. I.— List. t. 193,/. 30. 



1 See, too, the S. Contrarius and Spinulosus of Kuster (Ch. ix. 

 f. 985, 6, and 988, 9, 90), the S. Lamarckii, Digitatus, Fragilts 

 and Unicolor of Sowerby's Monograph (Thes Conch.), and the 



5. Ambiguus, Excavatus, Kostratus, Gracilis, Lima and Asiaticus 

 of Chenu's 'Illustrations.' The two last (II. C. Sp. t. 24, f. 7, and 

 t. 24, f. 1,4) are new to me. 



We have followed Deshayes in excluding the genus Gryph^ea. 



