LTOMESUS CANALICULATUS. 115 



to the recognised and existing species of different regions, is an exceedingly difficult 

 one. They run into one another in a very perplexing manner, possibly because in 

 Pliocene times they were nearer to the ancestral forms from which they had 

 sprung, when new variations would have a stronger tendency to revert to the old 

 types ; in discussing the Crag Neptuneas and Siphos we shall find ourselves 

 confronted with a similar problem. Forty years ago Sir J. W". Dawson expressed 

 the opinion that the northern Buccinums were involved in much confusion ; I fear 

 such is still the case. 



The subject needs a careful and thorough revision, but it must be undertaken 

 by a younger man than myself, who has more material, both Recent and fossil, at 

 his disposal. The Palgeontologist, moreover, who has only the shells to guide him, 

 must always be seriously handicapped for such a task. 



Adopting provisionally specific names at present current, I can only offer my 

 small contribution from the standpoint of a student of the English Crag, showing 

 that many Recent forms of the northern Buccinums, both European and American, 

 were more or less nearly represented in the North Sea during the Pliocene epoch. 



Genus LIOMESUS, Stimpson, 1865. 



Liomesus canaliculatus (Dall). Plate XII, figs. 1,2. 



1872. Trophon eleyans (?), S. V. Wood, Mon. Crag Moll, 1st Suppl., p. 22, tab. ii, fig. 6. 



1874. Buecinopsis canaliculata, Dall, Proc. Cal. Acad. Sti., vol. v, p. 252. 



1877. Buccinopsis elegans, Morcli and Poulsen, MS. list and plates iu Geol. Museum, Copenhagen, 



no. 24, pi. ii, fig. 5 (unpublisbed). 

 1883. Buccinopsis canaliculatus, KobeU, Martini und Chemnitz, Conch. Cab., ed. 2, vol. iii (Buccinum), 



p. 102, pi. Ixxxviii, fig. 10. 

 1902. Liomestis carialiculatus, Dall, Proc. U.S. Nat. Mus., vol. xxiv, p. 531, pi. xxxviii, fig. 2. 



Specific Characters..— Bhell short, ovato-conical ; whorls 5, nearly flat, diminish- 

 ing regularly to a blunt and depressed apex ; ornamented by strong and regular 

 spiral ridges closely crowded together ; suture well-marked ; mouth ovate, angulate 

 above ; outer lip thin ; canal short, wide, open, turning slightly to the left. 



Dimensions. — L. 32 — 35 mm. B. 18 — 20 mm. 



Distribution. — liecent : Behring Sea. 



Fossil : Butleyan Crag : Butley. Pliocene : Iceland. 



Remarks. — The shell from the Pliocene of Iceland here figured was referred by 

 Morch to Charlesworth's species, Atractodon elegans, although under the generic 

 name of Buccinopsis, probably because a similar form from Butley had been 

 described by Wood, though with some doubt {op. cit.), as an immature example of 

 that species ; Mr. A. Bell, however, who originally discovered the fossil in question. 



