142 Mr. E. A. Smith on Arctic MoUusca. 



Leda minuta, var., Fabricius, 



Thesaurus Conch, iii. pi. 228. f. 61, 62. 



Nucula parva, Sow. Conch. 111. f. 7 ; X. complanata, MoUer. 



Hab. Richardson Bay, 80° 2' N. lat., 70 fms. {Feilden). 

 The specimens from tlie above locality have the transverse 

 costas rather finer than is usual. 



Leda glacialis^ Leach. 



Area glacialis, Wood, Index Test. Suppl. p. 6, pi. 2. f. 6. 

 Nucula truncata. Brown, lUust. Conch, ed. 2, p. 84, pi. 33. f. 13, 

 N.portlanclica, Hitchcock, Reeve, Belcher's Last Arctic Voyage, vol, ii. 



p. 396, pi. 33. f. 3 a-b. 

 Leda siliqua, Reeve, A. Adams, Proc. Zool. Soc. 1856, p. 48 ; Reeve, 



Belcher's Voy. pi. .33. f. 4. 

 Nucula (Portlandia) arcfica, Morch (non N. arctica, Gray), Arctic 



Manual, 1875, p. 132. 

 Leda (Nucula) arctica, Jeffreys, Brit. Conch, ii. p. 158. 



Hab. Discovery Bay, 5 fms. (Feilden). 



In a young example of this species the posterior beak is 

 scarcely observable. 



Both Dr. Morch and Gwyn Jeffreys consider this species 

 the Nucula arctica of Gray. 



InParry's 'Voyage,' 1821, Appendix, p. ccxli, Gray describes 

 his species as "oval-elliptical, smooth, very slightly concentri- 

 cally wrinkled; epidermis yellowish green, glossy." The 

 form " oval-elliptical" and the smooth, glossy epidermis ap- 

 pear to me sufficient to show that the shell described by Gray 

 is different from that which it is considered to be by Morch 

 and Jeffreys ; and these characters are decidedly applicable to 

 the shell which Hanley, in his excellent monograph in the 

 ' Thesaurus Conchyliorum,' has referred to Gray's species. 



Again, Gray writes, " shell behind slightly produced, 

 gaping, edge entire." Both shells may be said to be slightly 

 produced; but certainly only the t7'ue arctica (that is, as deter- 

 mined by Hanley) shows a slight gape ; for in the other shell 

 (glacialis) there is not the faintest trace of an opening at the 

 produced or beaked end. Dr. Morch, in the ' Arctic Manual,' 

 p. 132, quotes N. arctica, Gray, Parry's ' Voyage,' and Wood's 

 Index, Suppl. t. 6. 



The last reference is evidently a mistake, and it should be 

 pi. 2, Aixa, fig. 6 ; and on referring to the text of the Supple- 

 ment, p. 6, the name referring to the figure is glacialis. 



Astarte semisulcata. Leach. 



Crassina semtsulcata, Leach, Append. Ross's Voy. p. 175 ; Sowerby, 

 Thesaurus Conch, ii. pi. 167. f. 21, 22 (as A. lactea) ; not A. semi- 

 su/cafa, Philippi, Abbild. ii. pi. i. f. 10. 



