BUCCINUM. 113 



B. UNDATUM, Linn. PL 75, figs. 306-321 ; PL 76, figs. 322-325 ; 



PL 78, figs. 361-366. 



" Shell conical above the periphery or centre of the body-whorl, 

 and somewhat truncated at the base, more or less solid (accord- 

 ing to the habitat), opaque, and usually lustreless ; sculpture, 

 numerous fine thread-like spiral ridges, some of which are much 

 stronger than others and are arranged in bands (from three to 

 seven small ridges between every large one) ; the whole surface 

 is covered with extremely delicate and close-set longitudinal 

 stride, which seldom, however, cross the spiral ridges so as to 

 cause any decussation ; the upper portion of the body-whorl and 

 of the four or five preceding whorls is often strengthened by 

 curved ribs or folds (like buttresses), of which there are from 

 twelve to fifteen on the penultimate whorl ; top whorl smooth ; 

 the base is girded by a very large, strong, and obliquely-twisted 

 keel. Color mostly yellowish white, tinged with reddish brown, 

 sometimes white banded with the latter color, or reddish brown 

 with a pink tinge and beautifully mottled with white ; inside 

 yellow, white, pale reddish brown or chocolate. Epidermis pale 

 brownish yellow, rather thin, usually rising into close-set laminar 

 folds, corresponding with the longitudinal stride, which form 

 short, spinous processes on the outer ridges. Spire regularly 

 tapering, apex blunt and irregular or mammiform ; whorls seven 

 to eight, rounded, the last occupying about two-thirds of the 

 shell ; suture deep ; mouth oval and somewhat expanded ; length 

 about one-half that of the spire ; canal open and deep, exhibiting 

 outside a similar and oblique notch ; outer lip semicircular, flexu- 

 ous, and having a large sinus or bay in the middle ; it slopes 

 outwards from the periphery ; edge reflected and thickened in 

 full-grown specimens ; inside slightly and indistinctly grooved ; 

 inner lip broad, consisting of a rather thick glaze on the pillar 

 and adjacent part of the body- whorl ; pillar smooth and highly 

 polished, microscopically freckled or pustulated by the lower 

 fold of the mantle. Operculum pale brownish yellow, rather 

 solid, more or less concave towards the nucleus ; the layers of 

 growth are laminar and numerous, resembling the epidermis in 

 texture. Length, 3*25 inches ; diameter, 2 inches. 



" Yar. 1. FLEXUOSA. More slender, with a produced spire ; 



