80 SUBULINA, WEST AFRICA. 



types, the length being 17, diam. 4, aperture 3.9 mm., whorls 

 over 9; the whorls are a trifle more convex than in Prince 

 Island specimens. The smooth embryonic shell has sub- 

 sutural crenulation as in S. striatella. The color is a slightly 

 brownish olivaceous yellow. 



7. S. VIVIPARA (Sowerby). PI. 11, figs. 94, 95. 



"The shell is commonly about an inch long, consisting of 

 about 9 volutions, the apex being blunt and rounded, the 

 volutions longitudinally striated and the base smooth; the 

 whole nearly white, semitransparent, and covered with a 

 thin olivaceous horny epidermis. 



' ' Three or four fully developed young shells may generally 

 be found upon breaking up a full-grown shell, occupying 

 commonly a great portion of the second, third and fourth 

 volutions from the base. The young ones consist of three 

 volutions before they quit the parent" (Sowerby). Local- 

 ity not given. 



Ackalina vivipara SOWERBY, The Malacological and Con- 

 chological Magazine, part 1, 1838, p. 27. PFR., Symbols iii, 

 p. 91; and in Philippi, Abbild. u. Beschreib. neuer Conchyl. 

 ii, p. 216, pi. 1, f. 5 (specimen received from Sowerby) ; 

 Monogr. ii, p. 264 ; Conchyl. Cab. p. 340, pi. 37, f . 15, 16.- 

 REEVE, Conch. Icon, v, pi. 16, f. 70. 



Pfeiffer describes a specimen received from Sowerby as fol- 

 lows: "Shell turrited-subulate, rather solid, longitudinally 

 closely rib-striate, rather shining, waxy-whitish. Spire elon- 

 gate, the apex rather obtuse, whorls 10, convex, the last one- 

 fourth the total length, angulate. Columella slightly arcu- 

 ate, not reaching the base, obliquely truncate. Aperture 

 semioval, the peristome thin. Length 20, diam. 5.5, aperture 

 5x3 mm." His figures of this shell are copied on my plate. 



This species differs from S. angustior in the following fea- 

 tures : " It is a stronger shell, less slender, and has usually a 

 whorl less in the same length. The rib-striae are nearly 

 parallel to the axis throughout, and are a little stronger. 

 The whorls are less convex, the last more acutely angular. 

 The aperture is wider, and the columella far more bluntly 



