194 JOURNAL OF CONCHOLOGY, VOL. I3, NO. 7, JULY, I9II. 



a " cylinder." Mediterranean specimens, which are not so rare, 

 mostly belong to the var. atiguslissima ; these have i8 whorls, and 

 are only i-20th of an inch in the widest part. A fine example from 

 Guernsey is ^8 in. long, and has 14 whorls besides the embryonic 

 ones ; these latter are 4-5, quite smooth, with the extreme tip turned 

 down or inverted. Although Jeffreys gives the number of whorls as 

 14-15, his figure has 10 only ; but Sowerby's has 14, and is also the 

 better figure. Still better is Boog Watson's figure, with 13 whorls 

 besides four embryonic ones.^ These apical whorls are rarely present, 

 the deep suture favouring their early dislocation. 



C. COStulata Moll. — Off the Shetlands, iii-i55f. (Simpson)! the 

 Minch 6o-8of., and North Shetlands 345f (Porcupine). 



Tiie apical whorls of this shell are not so suddenly narrowed as in 

 the foregoing species, and they consist of two only, the first one 

 being smooth, and the second one striated longitudinally and keeled. 

 Jeffreys gives the length as four lines, but his figure indicates three, 

 which is more correct, and the usual number of whorls is ten. 

 Sowerby's figure (pi. xv., fig. 13) is not this, nor has it any 

 resemblance ; but his supplementary figure has been taken from a 

 specimen of this shell, though badly. Some of the Norwegian and 

 Arctic specimens are larger and broader throughout, with the ribs 

 coarse and blunt instead of fine and sharp. 



The Rev. R. Boog Watson considers that C. costulata seems 

 "doubtfully entitled to rank as a Cerithiopsis." - The conchological 

 characters of Cerithium and Cerithiopsis are so intermixed in some 

 species that only an examination of the animal can rightly determine 

 their allocation. Several undescribed species from the Porcupine 

 Expedition are in this category. 



I have a specimen of C. horrida Jeffr.'' which was dredged off the 

 Eddystone in 3of., but as it is an imperfect example, without the 

 apical whorls, I think it better to wait for a more perfect one before 

 adding it formally to the British fauna, the embryonic whorls being 

 such a necessary feature in determining the species of this genus. 

 C. horrida resembles C. nietaxce in colour, in its obelisk-like shape, and 

 in its sharp-pointed tubercles (not papillose, as erroneously figured by 

 Jeffreys) ; but the whorls are not so convex, and it has only three 

 instead of four spirals. It varies, however, in size and degree of 

 sculpture quite as much as any of its congeners. 



Purpura lapillus L. — Gwyn Jeffreys has written that "the 

 shell of the male F. lapillus is longer, more slender, and has a 



1 Cerithiopsides from N. Atlantic, Jourii. Liiiii. See, 1S85, vol. xi.\., pi. 4, figs. 10, 10a. 



2 Challenger Gastropoda, p. 554. 



3 Moll. Lightning and Porcupine, Proc. Zool. Soc, 1885, p. 60, pi. vi., figs. 9-93. 



