783 



Ast. testa suborbiculari, cordata, obsoletissime radiatim sulcata, 

 laevi, vel sulcis concentricis obsoletis ; cardine dente centrali mag- 

 uo, subcrenato ; margine ventrali crenato. 



Smooth, or very obscurely grooved concentrically, and still more 

 obscurely radiated, orbicular, heart-shaped, with beaks prominent ; 

 central hinge-tooth in one valve, large and ragged, inner margin 

 crenated. 



Arctic Seas. 



16. Astarte fusca (pi. clxvii. f. 24), Poll. Tellina fusca, 

 Test. tab. 1. pi. 15. f. 32, 33. A. incrassata, Broechi, Deskayes, 

 ed. Lam. vi. p. 257. 



Ast. testa tumida, crassa, fusca, obscure rubro radiata, orbicu- 

 lari-cordata, versus umbones rotundatim lirata, postice subtruncata, 

 intus pallide fusca, margine crenato. 



Tumid, thick, of a dark brown, with sometimes obscure radia- 

 tions outside, paler (but still brown) within ; the concentric ridges 

 are smooth, round, without interstitial spaces, but generally obso- 

 lete from the middle to the ventral margin. 



Mediterranean. 



SPECIES NOT IDENTIFIED. 



A. bilunata, Conrad, Jay, Cat. 

 A. difficilis, Jay, Cat. Greenland. 

 A. kevis, Jay, Cat. Greenland. 

 A. Montagui, Gray, Turt. 



A. Portlandica, Mighels, Pro. Bost. Soc. Nat. Hist. 



LIST OF FIGURES IN PLATE CLXVII. 



{The Figure after the Name refers to the number of the Species.) 



Fig. 





Pig. 





1,2,3. 



A. sulcata, Cost. 1. 



13. A. 



subaequilatera, Swb.j. 6 



4. 



— elliptica, Brod. 2. 



14, 15.— 



castanea, Say, 15. 



5. 



— quadrans, Gould. 14. 



16.— 



semisulcata, Leach, 8. 



6, 7. 



— compressa, Mont. 12. 



17,18.— 



Arctica, Gray, 7. 



8. 



— Banksii, Leach, 11. 



19.— 



oblonga, Sowb. jun. 10. 



9. 



— triangularis, Mont. 13. 



20.— 



Arctica, Gray, 7. 



10. 



— crebricostata, Forbes, 5 . 



21-23. — 



lactea, Brod. 9. 



11. 



— intermedia, Sowb. jun. 3. 



24. — 



fusca, Poll, 16. 



12. 



— undata, Gould, 4. 







