378 MURICIDiE. 



rather distant ridges (of which there are about nine on 

 the principal whorls) that traverse the shell lengthways 

 (the apical coil excepted, which is merely striated in a 

 spiral direction), do not quite extend to the extreme base. 

 They are surmounted and rendered slightly nodose by the 

 very closely disposed and greatly depressed costre (of 

 which there arc four on the principal turns of the spire 

 and about ten on the body) that encircle the entire shell 

 (the nucleus excepted). The spire, which gradually at- 

 tenuates to a blunt mammillary apex, is composed of five 

 rather high volutions, that are simply and moderately 

 rounded, of rather slow longitudinal increase, and divided 

 by a fine but profoundly impressed suture. The body fills 

 from two-fifths to three-sevenths of the dorsal length, is 

 convexly rounded, but not ventricose, and attenuates 

 gradually to a bluntly acuminated extremity. The 

 mouth, which at times does not exceed one-third of the 

 ventral length, and at others occupies nearly two-fifths 

 of it, is not peaked posteriorly ; its shape is an oval, that 

 is produced below in a short and rather suddenly formed 

 canal, that does not lean to either side, and is not recurved. 

 The outer lip is more or less strengthened externally, is 

 moderately arched, simple, and neither lobated, nor sinu- 

 ated : it is armed within by short coarse raised lines or 

 crense, which are rarely present except in perfectly ma- 

 tured individuals. The inner lip does not swell out above, 

 is very concave in the middle, and has no sculpture, not 

 even a posterior pad ; the larger portion of it is occupied 

 by the almost perpendicular pillar, whose lip, though in- 

 conspicuous, is distinctly apparent. There is no vestige 

 of an axial perforation. The ordinary breadth of indi- 

 viduals is only a single line ; the usual length is the 

 fifth of an inch. 



