BELA. 991 
surface and canal distinguish this from B. exarata (a form of B. 
turricula). A var. acuta is described by Prof. Verrill as having 
a more slender form, with a longer and more acute spire and 
narrower aperture, the whorls more flattened, the nodules on the 
shoulder more prominent and sharper, and the carina higher; 
there are intermediate forms between this and the type. It is 
the B. mitrula of Verrill, not Lovén. B. Molleri, Reeve (PI. 27, 
fig. 27), is a rather problematical species, which Petit refers to 
B. Trevelyana, and Jeffreys to B. exarata, Moll. It appears to 
me to agree better with this species; it is a young shell, the 
figures being about twice its natural size, and its identification 
with B. concinnula is not sufficiently certain to authorize a 
change of name. 
B. TREVELYANA, Turton. PI. 33, fig. 65; Pl. 27, fig. 29. 
Shell somewhat thin, ovately fusiform, subventricose ; whorls 
six, slightly planate above the carina; aperture nearly equally 
contracted above and below; outer lip a little insinuate below 
the shoulder; surface lightly decussated by inconspicuous longi- 
tudinal plications, evanescent below the middle of the body-whorl, 
and close, fine revolving strie; whitish. Length, 8-13 mill. 
Europe, Spitzbergen, Nova Zembla, Boreal America. 
A smaller, more fragile and more delicately sculptured species 
than B. turricula, with shorter spire, and more oval form. The 
synonymy includes B. decussata, Macgill. (Pl. 27, fig. 29) and 
B. reticulata, Brown. The latter name has priority, but may be 
regarded as obsolete. A variety Smithii, described by Jeffreys, 
is doubtfully referred by Verrill to B. tncisula, Verrill (= 
decussata, Couth. var.). 
B. conoipEa, Sars. Pl. 29, fig. 61. 
Shell narrow, with long spire; whorls seven, convex, without 
carina; plications slight, somewhat sigmoid, almost obsolete on 
the body-whorl: everywhere covered with moderately ‘strong 
revolving strie; white. Length, 15 mill. 
Norway. 
B. Lyctaca, Forbes. PI. 27, fig. 28. 
" Shell rather shortly fusiform, whorls convex, narrowed at the 
upper part, longitudinally ribbed, with revolving elevated striz, 
