SAXICAVA. 89 



corresponding to the S. rhomhoides of Deshayes, the Mfjtilus prce- 

 cisus of Montagu, and doubtless the Hiatella arctica of Lamarck 

 (^Solen miiiutus, Lin.). 



Now all these varieties are found living promiscuously together, 

 and, as their shape is known to be greatly modified Ijy the circum- 

 stances under which they are developed, the rational conclusion is, 

 that they all pertain to the same species ; and the i)roba))ility is, 

 that they are identical with the European shell ; but under what 

 name to place them, and whether under one or more, it is now im- 

 possible to say. 



[It is now quite possible to say that the shell of the American At- 

 lantic coast is identical with that of the European and Arctic shores. 

 It is so multiform that Woodward states that five genera and fifteen 

 species have been manufactured out of varieties and conditions of 

 this protean species. Two species are generally admitted wdiich, in 

 their early stages at least, greatly resemljle each other in the two 

 spinous ridges along the posterior dorsal margin. But they are said 

 to have a constant difference in the anterior end, and in the pres- 

 ence or absence of an areolar space in front of the beaks. We 

 give a pretty extended synonymy of the two, according to latest 

 authorities. 



Saxicava arctica. 



Shell oblong, beaks at anterior fourth, rostrate in front, with a distinct areolar 

 space in front of the beaks ; diagonal ridge spinous. 



Mya arctica, Lin. Syst. Nat. 11 1. '5. — O. Fabr. F. Groenl, 407. — Turton, Conch. Diet. 



104. — Wood, Gen. Conch. 95. 

 Solen minutus, Lin. Syst. Nat. 1115. — Mont. Test. Br. 53, pi. 1, fig- 4. — Tcrt. Conch. 



Diet. 161. — Chemn. Conch. Cab. vi. 67, pL 6, figs. 51, 52. — Wood, Gen. Conch. 



139, pi. 34, figs. 5, 6. — DiLLw. Eecent Shells, i. 69. — Lam. An. sans Vert. 2d 



ed. vi. 57. — Wood, Lidex Test. pi. 3, fig. 33. 

 Mytihis pnecisus, Mont. Test. Brit. 165; Linn. Trans, vui. 112. — Dillw. Recent 



Shells, 305. 

 Hiatella arctica. Lam. An. sans Vert. 2d ed. vi. 443 — Flem. Br. Anim. 461 ; Br Mar. 



Conch. 59. — Crouch, Litrod. pi. 8, fig. 6. — Hanley, Eecent Shells, 1.50. — Cuv. 



E. Anim. pi. 110, fig. 1. 

 Anatina arctica, Turt. Dyth. Brit. 49, pi. 4, figs. 7, 8 ; Br. JLar. Conch. 42. 

 Agina purpurea, Tcrt. Dyth. Brit. 54, pi. 4, fig. 9; Br. Mar. Conch. 60. 

 Solen purpureus, Fle.m. Brit. Anim. 459. 



Saxicava purpurea. Brown, 111. Conch. Brit. 103, pi. 42, figs. 30, 31. 

 Saxicava rubra, Desh. Exped. Alger. Moll. pi. 66, figs. 18, 19 (shell and animal). 

 Saxicava rhomhoides, Desu. in Lam. An. sans Vert. 2d ed. vi. 153. 

 Saxicava arrtica, Desh. Elem. Conch, pi. 12, figs. 8, 9. — Phil. Moll. Sicil. i. 20, pi. 3, 



fig. 3, ii. 19. — Macoilliv. Moll. Aherd. 285. — Loven, Ind. Moll. Suec. 40. — 



Chenu, Man. de Conch, 25, fig. 113. 



