146 Bulletin 29 310 



posterior slightly oblique; outer lip typically with three denticles 

 within, the stronger posterior; basal fasciole present; shell scarce- 

 ly, if at all, perforate. Length 10, diameter 3 mm. 



This species is distinguishable by the presence of the fine re- 

 volving rib- on the periphery of the last fwhorl, which takes the 

 place of the sulcus in P. canaliciclata and semicanaliculata . 



The shell is dedicated to Mr. Axel Olsson by whom it was 

 found. 



Locality. — (Exp'd '16) Bluff 3, Cercado de Mao. 



Pyramidella {Callolongclicens) cercadensis, n. sp. 

 Plate 25, Figure 9 



Shell related to P. jamaicensis Dall, but slenderer and more 

 rudely sculptured; protoconch small and immersed; post-nuclear 

 whorls eight, convex, not flattened as in jamaicensis; periphery 

 of last whorl marked by an incised spiral line or narrow sulcus; 

 the preceding whorls are wound at a distance equal to one-third 

 of the whorl in front of the peripheral sulcus; suture channeled 

 and the anterior border is very minutely crenulated; columella 

 with a large posterior, horizontal fold and two oblique anterior 

 folds, the most anterior being very weak, scarcely discernible; 

 base of body whorl rounded; outer lip with two denticles, the 

 posterior much the larger; surface of shell polished, marked by 

 growth-lines and by very faint spiral striae. Length of shell 4.25, 

 width 1.40 mm. 



Locality. — (Exp'd '16) Bluff 3, Cercado de Mao (Rare). 



Pyramidella (Orinella) Arionis 

 Plate 25, Figure 10 



Shell small, slender, short, smooth and porcellanous; suture 

 distinct, whorls seven plus the rather large protoconch; the latter 

 is helicoid and consists of about one and a quarter visible whorls, 

 half immersed; post-nuclear whorls with their sides flattened, 

 somewhat turreted, axial height of each whorl equal to about 

 half its width; aperture small, columella with one large, promi- 

 nent plication. Length of shell 3.25, of body whorl 1.15, of 



