144 Mr. E. A. Smith on Arctic Mollusca. 



approach to riblets or fine costations, as in most other species 

 of this genus ; in fact the surface is not more striated than 

 in the American A. quadrans of Gould ; and the epidermis is 

 yellowish olive. 



On the contrary, A. striata has a dull surface and is dis- 

 tinctly but finely ribbed, and the epidermis darker and of a 

 brownish olive colour. It may be but a variety of the A. 

 compressa of Montagu, as suggested by Jeffreys (' Brit. 

 Conch.' ii. p. 316) ; but besides the usually finer ribbing, the 

 form is generally more elongate transversely and less trian- 

 gular. Another closely allied species is A. fabula of Reeve, 

 from which it differs in being differently sculptured. The 

 transverse ribbing in Reeve's shell is very peculiar towards 

 the umbones, and quite coarse in comparison with that on the 

 other portion of the surface. 



Another distinctive character is the length of the anterior 

 muscular scar. I have examined a good series of both species ; 

 arid I find that in A. fabula it is constantly longer than in 

 striata^ of course in shells of similar size. This is well 

 shown in Reeve's figures (in Belcher's ' Voyage ') of the two 

 species. I think it very probable, judging from the descrip- 

 tion and figure, that Gould's A. Batiksii is the A. fabula, 

 Reeve. 



Astarte fabula, Reeve, 



Belcher's Last Arctic Voy. 1855, vol. ii. p. 398, pi. .33. f. 5 a, b. 

 A. Banksii, Gould (non Leach), Invert. Mass. ed. 2, 1870, p. 125, fig. 

 438, probahlv. 



Hab. Dumb-bell Harbour and Discovery Bay (Fetlden). 



This species may be recognized by the peculiar ribbing near 

 the umbones. In this region the ribs are more strongly de- 

 veloped than on the rest of the surface of the valve, and are 

 not produced quite to the margins, so that in looking at the 

 shell with the umbones towards the eye the dorsal areas appear 

 comparatively smooth. 



? Astarte Warehami, Hancock, 

 Ann. & Mag. Nat. Hist. 1846, xnii. p. 336, pi. 5. f. 15, 16. 

 Hab. Franklin-Pierce Bay, 13-15 fms., bottom stony {H. 

 C. Hart) ; Richardson Bay, 80° 2' N. lat., 70 fms. {H W. 

 Feilden). 



I do not feel quite sure of the accuracy of the identification 

 of the specimens before me. They differ slightly in form from 

 Hancock's figure, being less elliptical by reason of the anterior 

 end being less produced ; but with regard to the ribs and epi- 

 dermis they agree exactly with tlie author's excellent descrip- 



