178 
ZOOLOGICAL LITERATURE, 
B. undulaturrij Moller,=ww<?a^Mm of Greene, Gould, and De Way, Catal. of 
Massachusetts and New York, =^lahradorense, Reeve. ^‘It.is not often that 
two species of shells can he found the differences between which are more 
difficult to define than those of the common whelks of the European and 
North American shores of the Atlantic.” 
B. cyanemUf Brugui^re, Beck, Reeve, =nmdatum of Fabr. Fn. Gronl.,= 
horeale, Leach, = humphreysianum, Moller, = hydrophanum, sericatum, tme- 
hrosum, and undulatum, Hancock, ^ gronlandicum of Morch. Greenland, Nor- 
thern Norway and Lapland. 
B. simplex, Midd. Schantar Island in the sea of Ochotsk. 
B. totteni, sp. n., Stimps. p. 386,= ciliatum, Gould MS., partly. Allied to 
B. humphreysianu7n, but the whorls plicated and more convex, the transverse 
sculpture deeper, and no deep colour. Banks of Newfoundland. 
The author has added an analytical table for distinguishing 
the species. However, as he says himself, in a genus 
where almost every specific character is -subject to great varia- 
tion, and where the species must be recognized rather by the 
gross amount of the characters than by the prominence of par- 
ticular ones, this is a very difficult matter. Such a synopsis 
is here only useful for the determination of the specific relations 
of perfect and well- characterized specimens 
Body-whorl angulated or carinated. 
Primary transverse ridges flat, secondary ridges inconspicuous. 
Shell thin, aperture not patulous, outer lip not sinuated. 
Whorls shouldered, aperture broadest above .... B. polare. 
Whorls scarcely shouldered, apert. broadest below. B. gi'cenlandicum. 
Shell thick and strong, aperture patulous, outer lip sinuated. 
Shell elongated B, donovani. 
Shell ovate B. glaciale. 
Prim, transv. ridg. convex, second, grooves very distinct. 
B. angtdosum. 
Body-whorl not angulated. 
Aperture narrow. 
Primary ridges flat B. striatum. 
Prim. ridg. Convex, tooth-like plait on columella. . B. ciliatum. 
Aperture broad. 
Longitudinal folds numerous, often interrupted or interposed. 
Primary ridges flat. B. plectrum. 
Prim. ridg. obsolete; second, conspicuous, crowded. B. tenue. 
Longitudinal folds not interrupted nor interposed. 
Shell thick and coarsely striated. ^ 
Sinus of outer lip near the suture, columella short. 
B. undulatum. 
Sinus of out. lip near middle, colum. projecting, B. undatum. 
Shell finely striated, usually thin. 
Secondary ridges easily distinguished from the primaries, which 
are often obsolete. 
Columella distinctly folded B. simplex. 
Columella smooth, not distinctly folded , , B. cyaneum. 
