88 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Mar. 6, 



2. Oil the MoUusca procured during the ' Lightning ' and 

 ' Porcupine ' Expeditions, 1868-70. (Part VI.') By J. 

 GwYN Jeffreys, LL.D., F.R.S., F.Z.S. 



[Eeceived February 23, 1883.] 

 (Plates XIX.. XX.) 

 GASTROPODA {continued). 

 Family VI. Scissurelltd^e. 

 1/ 1. ScissuRELLA CRisPATA, Fleming. 



S. crispata, Flem. Mem. Wern. Soc. vi. p. 385, pi. 6. f. 3 : B. C. 

 iii. p. 283, pi. vii. f . 2 ; v. p. 201, pi. Ix. f. 3, 3a, 3b. 



•Lightning' Exp. St. 2, 5. 



'Porcupine' Exp. 1869: 14, 25, 36 (var. aspera), 70. 1870: 

 Atl. 1, 2, 6, 9, 13, 16-1 7«, 24, 27-30, Tangier B. (and vars. angu- 

 lata and aspera) ; Med. 45, 50, Adventure Bank, off Ilinaldo's 

 Chair (var. aspera). 



Distribution. From Spitzbergen to Sicily and Azores, and from 

 Greenland to New England ; 4-790 fms. 



Fossil. Pliocene : Coralline Crag, Italy, Rhodes. Post-tertiary : 

 Norway and Sicily. 



iS. angulata of Lovdn and 8. aspera of Philippi are varieties ; the 

 latter corresponds with my variety paucicostata. S. angulata is 

 larger, and /S. aspera more conical with stronger and fewer striae. 

 The height of the spire and consequent contraction of the umbilicus, 

 as well as the number and strength of the riblets and spiral striae, 

 are variable characters. The variety aspera is more peculiarly 

 Mediterranean than the typical form. 



The animal was fully described by me in the ' Annals and Maga- 

 zine of Natural History ' for June 1870. 



f 2. ScissuRELLA UMBiLiCATA^ Jeffreys. (Plate XIX. fig. 1.) 



Shell forming a depressed sphere which is equally raised above 

 and below, rather thin, semitransparent, and somewhat glossy : 

 sculpture, none except very fine and close-set, but indistinct, lines of 

 growth : colour white : spire slightly raised : whorls 4-5, flattened 

 above and sloping outwards ; they rapidly enlarge, so that the last 

 or body-whorl considerably exceeds in size the rest of the shell : 

 slit long and central, equal in width, with upturned edges : mouth 

 nearly circular, but somewhat angulated where it is united to the 

 body-whorl below the peripheral keel : peristome continuous, al- 

 though not free in consequence of the inner lip being attached to 

 the shell : outer lip thin and sharp : inner lip spread on the lower 



' For Part I. see P. Z. S. 1878, p. 393 ; for Part II. see P. Z. S. 1879, p. 553; 

 for Part III. see P. Z. S. 1881, p. 693 ; for Part IV. see P. Z. 8. 1881, p. 922 ; and 

 for Part V. see P. Z. S. 1882, p. 650. 



^ Umbilicate. 



