248 PYRAMIDELLID.E. 



C. FORMOSA, Jeffreys. 



Moderately large, Avhite, slenderly turreted ; lower wliorls 

 flattened ; intervals of the straightish ribs encircled with about 

 five spiral costellre on each turn, and excavated above the pro- 

 found suture ; mouth not a sixth of the entire length. 



Plate XCIII. fig. 5. 

 Odostomia formosa, Jeffreys, Ann. and Mag. N. H. ser. 2 (1 848), vol. ii. p. 347. 



This extremely rare .shell is so slenderly turreted as 

 almost to be aciculate ; it is comparatively -strong for the 

 genus, only very slightly glossed, opaque in the very few 

 examples we have seen (perhaps dead specimens), and of a 

 pure and uniform white. The sculpture of the volutions, 

 which terminate in a fine point, consists of about twenty 

 prominent nearly straight longitudinal ribs, that are tole- 

 rably strong, of about the same breadth as their intervals, 

 not continuous from whorl to whorl, but suddenly dwin- 

 dling off below to a bluntish point, and about five intersti- 

 tial series of scarcely elevated spiral costelloe, each of which, 

 when examined by a powerful lens, is found to be composed 

 of from three to five raised lines. The whorls, the majo- 

 rity of which are nearly flat, and subturriculated, although 

 some of the superior ones are more rounded, are of very 

 gradual increase, and are divided by a distinct and but 

 slightly oblique suture, that appears remarkably broad, 

 owing to its limits being enlarged by the inferior attenuation 

 of the costee, and by an excavation of their intervals, which 

 produces a sudden contraction at the base of each volution, 

 and is continued in a revolving line along the bottom of the 

 body-whorl. The .spiral interstitial lines seem to be rather 

 indistinctly continued upon the base of the shell, which is 

 moderately rounded, and neither abruptly compressed, nor 



