290 CYLICHNA. 



Reg. Arct. Norv., p. 283, pi. 17, f. 12; pi. 11, f. 4. BUQ. DAUTZ. 

 &DOLLF., Moll. Rouss. i, p. 521, pi. 64, f. 1-3. WATSON, Chal- 

 lenger Gastrop., p. 663. MOBIUS, in Die Zweite Deutsche Nord- 

 polarfahrt, 1869-70, (Koldwey), ii, p, 250, pi. 1, f. 4-9 (digestive 

 tract and dentition). SMITH, P. Z. S. 1871, p. 738; P. Z. S. 1890, 

 p. 297. A. AD. in Sowb., Thes.iii, p. 590, pi. 125, f. 132. FORBES 

 & HANLEY, Hist. Brit. Moll, iii, p. 508. Bulla oliva GMEL., Syst, 

 Nat. (xiii), p. 3433. P>. cylindriea BRUG., Encycl. Meth., p. 37 not 

 of Gmelin. B.producta BROWN, Illustr. Conch., pi. 19, f. 15, 16. 



B. convoluta BROCCHI, Conch, foss. Subapp., p. 277, pi. 1, f. 7. 

 SCACCHI, Catal. Conch. Req. Neap., p. 10, 1836. Cylindrella alba 

 SWAINSON, Malacol. p. 326, fig. 94b. 



The cylindrical form and for the group large size of this species 

 readily distinguish it from other European forms. The literature of 

 the species is extensive, and only the more important references are 

 given above. For others see Moll. Roussillon, Forbes and Hanley, 

 and the Challenger Report. 



Var. LINEARIS Jeffr. Shorter, nearly smooth and decidedly 

 glossy, marked at each end with yellowish-brown spiral lines, few 

 and remote at the top, close-set at the bottom. Apex invariably 

 perforated and showing part of the internal spire. 



England; St. Helena. 



C. cylindracea has been reported from Bombay by Melvill and Aber- 

 crombie. 



C. ALBA Brown. PL 60, fig. 16. 



Shell oblong, somewhat cylindrical, tapering toward both ends. 

 White, covered with a pellucid buff cuticle ; polished ; surface 

 sculptured by extremely close, fine, superficial spiral stria, visible 

 only under a strong lens, on fresh specimens. Aperture narrow 

 above, dilated below, wider than in C. cylindracea ; the lip curved 

 as in that species. Columella thick but hardly folded. Apex im- 

 perforate, somewhat concave, bounded by a keel. Alt. 5i, diam. 2 3 

 mill. Tooth-formula 5,1.1.1,5. 



Spitsbergen and Greenland to the Bay of Biscay, and to Cape Cod. 



Volvaria alba BROWN, Illust. Conch. G. B., p. 3, pi. 19, f. 43, 44. 

 Cylichna alba LOVEN, Ofversight Vet. Akad. Forh. 1846, p. 142. 

 JEFFR., Brit. Conch, iv, p. 417, pi. 8, f. la (dentition) ; v, p. 223, 

 pi. 93, f. 6 ; Ann. Mag. N. H. (4), x, p. 241 ; (4), xix, p. 333 ; (4) 



