226 PROCEEDINGS OF THE ACADEMY OF 



shell ; peristome thin ; columella arched, slightly callous, and the 

 plait small and very oblique. 



Lengtli 4^ mill, 



Hab. Yiti Isles. (Coll. Garrett.) 



A single perfect and an immature example found washed up on 

 the sands. It may be distinguished b}' its shouldered whorls, dis- 

 tant ribs, and hyaline structure. 



Odostomia crystallina, Garr., pi. 3, fig. 49. 



Shell elongate, subulate, rather thick, sub-pellucid, smooth, 

 shining white; spire long, outlines slightly convex, apex acute; 

 whorls 11-12, nearly plain, last one short, rounded, cancellated 

 with microscopical longitudinal and transverse strife ; suture im- 

 pressed ; aperture vertical, broad ovate, acutel}^ angular above, 

 rounded below, about one-fifth the length of the shell ; peristome 

 thin, simple ; columella arched, callous, and the plait stout. 



Length 7^ mill. 



Hab. Yiti Isles. (Coll. Garrett.) 



Two perfect examples found on a sandy mud-flat. Deep in the 

 throat may be observed several exceedingly delicate revolving 

 lamellae, which, as seen through the sub-pellucid shell, look like 

 engraved lines. 



Odostomia lutea, Garr., pi. 3, fig. 50. 



Shell elongate, subulate, smooth ; shining, luteous-yellow ; spire 

 long, the upper half tapering more rapidlj' than the lower; apex 

 acute ; whorls 9-10, flatly convex, last one sub-angulate near the 

 base, obsoletelj^ striated by lines of growth ; suture impressed and 

 margined beneath ; aperture widely ovate, about one-fuurth the 

 length of the shell ; peristome thin, nearly straight, obsoletely 

 angulated at the base; columella slightly callous, somewhat re- 

 flexed so as to form a slight umbilical fissure, and distinctlj' 

 plaited. 



Length Y mill. 



Ilah. Yiti Isles. (Coll. Garrett.) 



Three examples found on a sandj' mud-flat. 



Odostomia obeliscus, Garr., pi. 3, fig. 51. 



Shell elongate, subulate, thin, hyaline, white ; spire long, flat- 

 tened in outline, apex acute; whorls 10, plano-convex, tiie last 

 one short, rounded, decussated bj' microscopical longitudinal 



