Fusus. 425 



Although the suhstance of the shell is thick, yet at 

 times there is a slight degree of transluceney ; the colour 

 is usually of an uniform tint that ranges from pure white 

 to orange-brown ; occasionally the stages of increase are 

 indicated by indistinct broadish streaks, of a more intense 

 shade than the general tint. The depressed costellar 

 strise, with which the principal volutions are encircled 

 throughout, and which are often rendered wavy (fre- 

 quently, indeed, interrupted) by coarse wrinkles of in- 

 crease, are so closely disposed that finer intermediate ones 

 start forth wherever the space permits. They are ge- 

 nerally of about equal magnitude throughout, somewhat 

 finer beneath the sutures, somewhat coarser on the extreme 

 base ; occasionally, however, a few of them, chiefly on the 

 upper third of the body and near the middle of the larger 

 turns of the spire, become more elevated than the rest (as 

 in the carinatus of Turton), yet never assume that coarse 

 ridge-like appearance that is characteristic of the more 

 distantly striated carinatus of Pennant. Besides the 

 smooth apical nucleus, which consists of two coils, the first 

 bluntly mamillary and swollen, the second narrowly cylin- 

 drical, the spire comprises four other whorls that are of 

 fast longitudinal increase, of moderate height (at least half 

 as long as broad, often indeed in the slender forms the 

 length is to the breadth as three to five), moderately 

 ventricose, often subangulated rather above the middle, 

 much tapering above, and in that case shelving with some 

 little retusion (not deeply concave) towards the fine yet 

 profoundly impressed moderately slanting suture; more 

 perpendicular below. The body, which is swollen above, 

 and thence attenuates to a shortish and scarcely recurved 

 beak, is of a curved and truncated fig-shape ; its basal 

 declination is not abruj)t, but is convex or rounded. 



VOL. III. 3 I 



