116 



Hah. Singapore ; on dead shells, ten fathoms, in coarse sand and 

 gravel. Mus. Cuming ; one small specimen. 



5. Anomia ach^us. 



Shell purplish, smooth ; umho rather acute ; upper valve generally 

 convex ; inside purplish white. 



Upper muscular scar large, lower edge slightly arched; lower 

 scars 2, small, nearly equal-sized ; the hinder rather lower than the 



other. 



Hab. Indian Ocean, Kurachee, mouth of the Indus. Brit. Mus. 

 and Mus. Cuming. 



Major Baker has kindly sent to the Museum a very large series of 

 the dorsal valves of this species, collected at Kurachee. They are ex- 

 tremely variable in form, surface, colour and thickness, and they also 

 oifer considerable variety in the disposition of the muscular scar. In 

 all the upper scar is largest, but variable in shape from round to 

 broad cordate. In most the two lower scars are close together, but 

 separate, and nearly on the same line. In others the lower scar is 

 rather lower than the middle one, and in a few (four) specimens, which 

 are mostly produced posteriorly, the lower scar is much lower ; that 

 is to say, in some the upper edge is parallel with the lower edge of 

 the middle one. In one specimen the two lower scars are on the 

 same line, and are confluent together, forming a scar about the same 

 size as the upper scar, yet showing that the lower scar is formed by 

 two muscles ; so that this valve cannot be confounded with a Placu- 

 nanomia. 



The examination of this series of specimens from the same locality 

 I think shows, that though the comparative size and disposition of the 

 scars may furnish good characters for the distinction of the species, 

 yet they are not to be implicitly relied on. 



6. Anomia belesis. (Mollusca, pi. 4. fig. 3, 4.) 



"White or red ; the upper part of the centre of the dorsal valve 

 white, externally radiately striated; apex acate, at some distance 

 from the dorsal edge. 



Upper valve with three separate scars, the upper one very large 

 oblong, and rather transverse; two lower ones very small, nearly equal- 

 sized, and nearly on the same line. 



Hah. Indian Ocean ? General Hardwicke. Brit. Mus. 



fff American. 



7. Anomia ACONTES. 



Yellowish white, suborbicular, flat, smooth ; disk pearly. 



Upper scar moderate, siibcircular ; lower scars smaller, distant, 

 circular, subequal, the lower one nearly on a line with the lower edge 

 of the middle one. 



Hab. Jamaica ; Gosse. Mus. Cuming ; one small specimen. 



8. Anomia fidenas. 



White, pearly, thin, flat, smooth externally, pearly within, with a 

 thick white disk. 



