rusus. 335 



landicus and F. gracilis (which latter he described as 

 F. Listeri) in the ' Transactions of the Society of Natural 

 Sciences at Hamburg/ The young of the present shell 

 appears to be the F. Sabini of Hancock; Buccinum 

 Sabinii of Gray is another species. Dr. Mb'rch tells me 

 that he regards F. Islandicus as bearing the same re- 

 lation to F. gracilis as F. despectus does to F. antiquus. 

 The Tritonium Islandicum of Loen is F. Berniciensis. 



/sf. 0% 5. F. GRA ; eiLis*y\Da Costa.) . 



Buccinum gracile, Da Costa, Br. Conch, p. 124, t. vi. f. 5. F. Islandiws, 

 F. & H. iii. p. 416, pi. ciii. f. 1, 3, and (animal) pi. SS. f. 2. 



BODY white, with frequently a tinge of pale yellow : pdllial 

 tube short but broad, upturned when the animal crawls : pro- 

 boscis cylindrical, very long and muscular, fleshcolour on the 

 underside : tentacles triangular and flattened, short, with 

 rounded tips ; they diverge in consequence of being separated 

 by the head- veil, which forms an intervening membrane : eyes 

 small and black, nearly sessile, about halfway up the tentacles, 

 on their outer side : foot oblong, squarish and double-edged in 

 front, with angular corners, expanded at the sides, and bluntly 

 pointed behind. 



SHELL broader near the base than towards the other extremity, 

 rather solid, almost opaque, somewhat glossy: sculpture, nume- 

 rous slight spiral ridges, which are denned on the upper whorls 

 by impressed lines ; there are about 16 on the penultimate 

 whorl, 14 on the antepenultimate, 12 on the next, 10 on the 

 next, 8 on the next, and 6 on the next whorl, the upper 

 two whorls being smooth ; the ridges extend to the suture on 

 each side ; lines of growth curved and very fine : colour white 

 (with rarely a tinge of fleshcolour) beneath the epidermis: this 

 is membranous, usually yellowish-brown, lemoncolour, or even 

 of a paler hue in specimens from deep water ; the epidermis 

 is frequently wanting below the periphery, near the upper 

 part of the inner lip, so as to expose a broad triangular patch 

 the base of which is uppermost : spire elongated and abruptly 

 tapering ; apex irregularly mammiform, and twisted in front, 

 but not prominent or forming a bulbous point as in the last 



* Slender. 



