SIPHO EBUR. 197 



shorter, but it differs from the latter in its regularly spiral or plaiiorl)oi(l apex. It 

 appears to be represented in northern seas by S. glaher, in which, however, the 

 apex is bulbous. 



I have found a number of specimens at Oakley corresponding more or less 

 closely with Jeffreys' description and figure of >S'. Jrjjh'j/sianus ; unfortunately the 

 apices are invariably imperfect. Wood claimed this form as a Crag species, but 

 did not figure it ; I have given a representation of one of the Oakley fossils with 

 that of a Recent specimen from the Devonshire coast. 



Sipho ebur (Morch). Plate XXI r, figs. 13, 14. 



1869. Fasus {8i})honorhis) ebur, Morch, Joiirn. de Conch., vol. xvii, p. 398. 



1882-1901. Neptunea (Siphonorbis) ebur, Friele, Norske Nordh. Exped. (MoUusca), pt. i, p. 18, 



pi. ii, fig. 20, 1882 ; pt. iii, p. 105, 1901. 

 1887. Neptunea ebur, Kobelt, Icou. schalentrag. europ. Meeresconch., vol. i, ]>. 78, pi. xiii, figs. 5, 6. 

 1899. Sipho (Tritonofusus) ebur, Posselt, Medd. cm Gronl., vol. xxiii, fig. 182. 

 1912. Sipho (Siphonorbis) ebur, Dautzeuberg et Fischer, Camp. Scient. Pr. Monaco, vol. xxxvii 



(Mollusques), p. 93, pi. iii, fig. 16. 



Specific Characters. — Shell fusiform, thin and fragile ; whorls convex ; spire 

 short, ending in a blunt and planorboid apex ; suture deep ; ornamented by very 

 fine and rather inconspicuous thread-like spiral lines, crossed by numerous and 

 excessively delicate lines of growth ; body- whorl tumid, deeply excavated below ; 

 mouth oval ; canal short and open ; outer lip thin, regidarly curved ; inner lip 

 forming an exceedingly fine glaze, adherent to the flexuous pillar. 

 Dimensions. — L. 50 mm. B. 25 mm. 

 Distribution. — Recent : northern Seas, from 90 to 223 fathoms (Friele). 



Fossil : Waltonian Crag : Little Oakley. 

 Remarks. — There seems some confusion as to the shells described as 8. ebar, 

 8. 8arsii and 8. Moehii which some authorities regard as different varieties of one 

 species. 



The first was described by Morch in 18G9, the second by Jeffreys in the same 

 year ; unfortunately neither was figured. 8. ebur was figured by Mr. Friele in 

 1882. I have a Recent specimen in my collection (PI. XXII, fig. 13) which Dr. 

 Nordgaard kindly sent me as typical of this species, and I have a similar one, fossil 

 and imperfect (fig. 14), from Oakley; both agree with Mr. Friele's figure; they 

 are fragile, with fine, irregular and inconspicuous sculpture and a clearly marked 

 canal. 



On the other hand, Messrs. Dautzenberg and Fischer, and Prof. Kobelt {op. cit.), 

 figure under the same name a somewhat different form, which is larger, and has a 

 short, wide, and open canal. The former authorities state, however, that immature 

 examples of 8. ebur have a rudimentary canal which disappears in the adult. 



