FAMILY 



Animal having a retractile proboscis ; tentacles close together, 

 long and pointed, the eyes on slight elevations near their outer 

 bases ; mantle-margin simple, with a rudimentary siphonal fold ; 

 foot truncated in front, extending far in advance of the head. 

 Jaws oval or semicircular, spiny, or denticulated only on the 

 margin; radtila composed of elongated unciform or aciculated 

 teeth, many in a series (PI. 11, fig. 30). Sexes distinct. 



Shell usually white and polished, turriculated, perforate, but 

 the umbilicus frequently covered by an expansion of the inner 

 lip-margin ; whorls numerous, convex, usually loosely coiled, 

 often barely or not at all in contact ; aperture entire, circular 

 or oval. Operculum corneous, few-whorled, nucleus nearly 

 central. 



These mollusks are somewhat closely allied to the lanthinse, 

 of which they may be regarded as creeping representatives. The 

 form of the shell remotely suggests Turritella. 



Synopsis of Genera. 



Genus SCALARIA, Lam., 1801. 



Shell mostly pure white and lustrous, umbilicated or imper- 

 forate ; spire elongated, the apex more or less inflected ; whorls 

 numerous, rounded, in contact or separated, ornamented with 

 longitudinal ribs or thin lamellae, often continuous across the 

 suture ; peristome entire, thickened, reflected. Animal as in the 

 family description. They are predaceous. Dr. Gould fed them 

 on raw beef, which they eat voraciously, They exude a purple 

 fluid when irritated. 



The genus commenced in the Trias, and has continued its de- 

 velopment to the present time ; about 200 fossil species have 

 been described, and not far from the same number recent. They 

 are found from low water to 80 or 100 fathoms and occur 

 throughout the world, the Arctic seas furnishing representations 

 of peculiar type ; but the largest, finest and most typical species 

 4 (49) 



