142 Mr. E. A. Smith an Arctic Mollusca. 



Leda minuta, var., FabriciuSj 



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



Nucidaparva, Sow. Conch. lU. f. 7 ; X. co7tiplanata, Mdller, 



Hab. Eicharclson Baj, 80° 2' N. lat., 70 fm.s. [Feilden). 

 The specimens from tlie above locality have the transverse 

 costse rather finer than is usual. 



Leda glacialis^ Leach. 



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



Nucula truncata, Brown, lUust. Conch, ed. 2, p. 84, pi. 3'3. f. 13. 



iV^. portlandica, Hitchcock, Reeve, Belcher's Last Arctic Voyage, vol. ii. 



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

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



Belchers Toy. pi. 33. f. 4. 

 Nucula (Porfhindia) arctica, Morch (non N. arctica, Gray), Arctic 



Manual, 1875, p. 132. 

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



Hah. Discovery Ba}^, 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 Nticida arctica of Gray. 



InPain-y'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 true 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^ Grray, Parry's ' Voyage,' and Wood's 

 Index, Suppl. t. 6. 



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

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

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



Astarte seniisulcafa, Leach. 



Cramna semisulrata, Leach, Append. Ross's Voy. p. 175; Sowerby, 

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

 sukata, Philippi, Abbild. ii. pi. i. f. 10. 



