CALLIOSTOMA. 391 



^ Separated from C. zizyphinum by the narrower, more elevated 

 form, narrower supra-sutural fasciole, more polished smoother 

 surface. 



The mutations in color are numerous; the varieties enumerated 

 by Monterosato are scarcely important enough to describe here, 

 and besides, are described by their names. 



Var. DUBIUS Pliilippi. PI. 18, figs. 19, 20. 



Smaller than typical conulum, with stronger spiral sculpture on 

 the lower whorls; base flat. Alt. 15, diam. 13 mill. It is larger 

 than C. laugieri, with more granulation on the upper whorls. 



Mediterranean and Adriatic Seas. 



The form called var. SPONGIARUM B., D. & D. (pi. 65, fig. 69) is 

 thin shelled, the earlier whorls smooth, not granulate, the re- 

 mainder with supra-sutural fasciole and 3 well-marked spiral 

 furrows. Base of the last whorl traversed by numerous concentric 

 cords; color light gray, longitudinally flamed, the spiral furrows 

 breaking the flames in places into a tessellated pattern. There is 

 also a uniform violet-colored form (violacea Monts. not Risso), and 

 a white one (albida Dautz.). This well-marked variety lives on 

 sponges in the Gulf of Gabes. Z. basalt* Monts., ms. is a synonym. 



C. NOCTURNUM Philippi. PL 18, figs. 3, 4. 



Shell exactly conical, imperforate, smooth, violaceous green ; whorls 

 plane, margined by a slightly elevated cingulus at the base*marked 

 by regular distant impressed incremental strice ; last whorl obtusely 

 angular; base nearly plane, smooth ; aperture rhombic ; columella 

 very oblique, cylindrical, entire. (Philippi.) 



Habitat unknown. 



T. nocturnus PHIL., Conchyl. Cab., p. 112, t. 18, f. 9. 

 I have before me a single specimen of unknown history, referable 

 to this species. It evidently belongs in the immediate vicinity of 

 0. conulmn, and is probably synonymous, differing in the darker 

 color (livid-brown in my example), and distant, impressed stria of 

 increment The upper whorls are granose ; the suture has a narrow 

 flat margination above ; there are no concentric lines on the base, 

 except, perhaps, slight indications of them at the center. 



C. GUALTERIANUM Philippi. PI. 17, fig. 30. 



Shell conical-elevated, imperforate, polished, solid, yellowish-brown 

 or olive, clouded with brown, the earlier 4 whorls dark bluish or 



