779 



Ast. testa subquadratti, compressa, solidti, antice brevi, postice 

 subangulata, subtruncata; sulcis rotundatis, distinctis, regulari- 

 bus ; margine crasso, intus plerumque crenulato. 



Of a squarish form, with regular ribs of medium size and num- 

 ber. The margin is generally crenulcd, but the variety named 

 Crassina Scotica is not so. The name A. Danmoniensis is lost, on 

 account of the priority of the specific name sulcata. In this and 

 in one or two following species the ribs are frequently nearly ob- 

 solete towards the ventral margins and back. 



2. Astarte elliptica (pi. clxvii. f. 4), Brown, Illus. Conch, 

 p. 96. pi. 38. f. 3; Iianley, Recent Shells, Suppl. pi. 14. f. 36 ; 

 Forbes and Hanley, B. Moll. pi. 30. f. 8. Astarte semisulcata, 

 Moller (not Leach). Crassina sulcata, Nilsson, Nov. Act. Holm. 

 1822. p. 187. pi. 2. f. 1, 2. Crassina ovata, Brown, Edin. Jour. 

 Nat. and Geog. Sci. pi. 1. f. 8, 9. 



Ast. testa oblonga, subquadrata, compressa, postice truncata, 

 costellis concentricis postice et versus margines plerumque obso- 

 letis ; margine intus lsevi, impressionibus muscularibus magnis. 



Like the Scotica variety of sulcata, it has a smooth inner mar- 

 gin ; like sulcata as I understand it, it has the truncated form at 

 the posterior side ; like all the species of the group, it is some- 

 times destitute of ribs on the back and ventral margins. It is 

 longer than sulcata, and (in Mr. Hanley's specimen) has much 

 larger muscular impressions. 



North Europe. 



3. Astarte intermedia (pi. clxvii. f. 11), Sowerby ', jtin. 



Ast. testa ovali, compressa, lirata, utrinque acutiuscula, liris 

 subfrequentibus, nonnunquam prope marginis evaiiidis; margine 

 intus laevi. 



My experience in the variations of the genus is hardly sufficient 

 to enable me to say whether the distinction now proposed will 

 stand, but it seems to me more important than the one between 

 sulcata and elliptica. A. intermedia differs from both these in 

 having the ends rather sharp than rounded or truncated. It dif- 

 fers from the American species untlata in having a much larger 

 number of ribs. 



North Europe. 



4. Astarte undata (pi. clxvii. f. 12), Gould, Invert. Mass. 

 p. 80. A. sulcata, Auct. Amer. A. latisulca, Hanley, note, p. 

 87. A. Mortoni, Adams, U.S. (ubi?). 



