106 PLIOCENE MOLLUSCA. 



very differently sculptured shell originally described in the Zoology of Beechey's 

 Voyage as B. angulosum, remarking that " most of these arctic Buccinums have 

 two forms, apparently correlated with sex, the males being in several species far 

 smaller, more slender, and less shouldered and flaring at the aperture ; that the 

 female has to carry the material for the enormous ovicapsular mass is a sufficient 

 reason for their difference in form, and probably for the difference in size. Apart 

 from this, many of the species have mutations of the coarser sculpture, which 

 result in very unlike individuals." ^ In the present case the shell of the female is 

 buttressed by strong and coarse longitudinal costce, and the base of the body- 

 whorl is angulate ; in that of the male, according to Dr. Dall, the whorls are 

 regularly convex and without such ornament. The first is found living on the 

 arctic coasts of Europe and of America ; the second has only been recorded from 

 the Alaskan region. The question of sex however, introduces a new complication 

 to the study of the fossil Buccinums. 



Buccinum fragile (Yerkriizen), G. 0. Sars. Plate VIII, fig. 0. 



1878. Buccinum fragile, Verkviizen, MS., Gr. 0. Sars, Moll. Reg. Arct. Norv., p. 257, pi. xxiv, fig. G. 

 1883. Buccinum frarjile, Kobelt, Martini uud Chemnitz, Conch. Cab.,ed. 2, vol. iii (Buccinmn), p. 42, 



pi. Ixxxii, fig. 7. 

 1887. Buccinum fragile, Kobelt, Icon, schaleutrag. europ. Meeresconih., vol. i, p. 110, pi. xix, fig. 4. 



Specific Characters. — Shell very thin and fragile ; whorls decidedly convex, the 

 last ventricose, much the largest, two-thirds the total length, the upper whorls 

 only plicated ; surface covered with distinctly marked, wavy and unequal spiral 

 lines, not very prominent ; suture deep ; mouth oval, angulated above, rather less 

 than half the length of the shell ; outer lip expanded, very thin ; inner lip forming 

 a slight glaze on the pillar ; canal very short and open. 



Dimensions. — L. 50 mm. B. 30 mm. 



Distribution. — Recent : Einmark, Nova Zembla, Spitzbergen, Greenland. 

 Fossil : Waltonian Cras: : Little Oaklev. 



BemarliS. — I have obtained one or two specimens of this northern and 

 exceedingly fragile species at Oakley, for the identification of which I am indebted 

 to Dr. 0yen. They correspond, moreover, in form and sculpture with a Recent 

 shell I have received from Dr. Sparre Schneider, obtained at Vadso at a depth of 

 100 fathoms. 



Mr. Eriele identifies B. fragile with B. undulatiim, Moller. MM. Dautzenberg 

 and Fischer consider it nearly allied to B. Tottenii. 



> See also H. and A. Adams, Gen. Eec. Moll., vol. i, p. 108, 1858; and Eev. A. H. Cooke, Cambr. 

 Nat. Hist., vol. iii, p. 134, 1895. 



