BITTEUM. 153 



B. ESURIENS, Carp. PI. 30, fig, 16. 



Like the preceding, of which according to Carpenter it is possibly 

 a degraded variety, but much smaller. Length, 6*5 mill. 



Vancouver's 1st. to San Pedro, Cal. 



B. QUADRIFILATUM, Carp. PL 29, fig. 91. 



Whorls slightly convex, with well-impressed suture, narrow, with 

 close longitudinal ribs, crossed by four raised spiral threads, base of 

 body whorl smooth, light ash color varying to chocolate, interior 

 chestnut color. Length, 8 mill. 



& Pedro S. Diego, Cal. 



B. ASPERUM, Gabb. PI. 30, fig. 7. 



A stouter species than B. quadrifilatum, the whorls slopingly 

 convex, forming an obtuse angle above the suture, sculpture simi- 

 lar, but stronger. Length, 10 mill. 



Southern California. 



Described as a fossil of the pleistocene of the same region, but has 

 since been discovered recent. B. rugatum, Carp., is a synonym. 



B. ATTENUATUM, Carp. PI. 30, fig. 8. 



With about 10 rather narrow, rounded whorls, with scarcely 

 impressed suture, with longitudinal riblets, distinct only at the top 

 of the whorls, where they are decussated by two spiral lines, the 

 spiral sculpture also becoming fainter below, base of body whorl 

 prolonged, with about six spiral striae. Length, 10 mill. 



California. 



B. PERUVIANUM, d'Orb. PI. 30, fig. 21. 



Ventricose, whorls slightly convex, granulated by longitudinal 

 rounded ribs and spiral striae, chestnut color. Length, 7 mill. 



Near Arica, Peru. 



B. PIGRUM, Watson. PL 30, figs. 4, 2, 3, 11. 



With about 21 flatly rounded longitudinal ribs, and subequal 

 interspaces, with three fine spiral threads, forming rounded tubercles 

 on the ribs, suture defined above by a raised thread, which termi- 

 nates the sculpture on the body whorl, being smoother on the base ; 

 dead white. Length. 9'5 mill. 



Tristan da Cunha Is. 



I think B. lustince (fig. 2), B. philomelce (fig. 3), and B. cedonicum, 

 Watson (fig. 11), are merely young shells of the species; they are 

 all from the same locality. 



