MUSEUM OF COMPARATIVE ZOOLOGY. 49 



by the plications, or not ; the base is usually more finely sculptured and some- 

 times quite smooth except for lines of growth. Aperture quite oblique ; pil- 

 lar with a blunt tooth as in other species of the genus ; lip somewhat reflected, 

 thickened inside, basal callus not very thick. Alt. 7.0±. Maj. diam. 6.75±. 



Sand Key, 125 fms. ; Station 2, 805 fms. ; Sigsbee, off Havana, 450 fms. ; 

 off Cape San Antonio, 1,002 fms. ; Yucatan Strait, 640 fms. 



This shell is so variable that I should be disposed to think Watson's Turbo 

 (Collonia) indutus a mere abnormally smooth specimen, were it not that he 

 does not figure the tooth on the pillar. It is very probable, however, that 

 they will tmni out to be varieties of the same species. 



CALLOGAZA n. g. 



Shell resembling Gar.a Watson, but with the umbilical pad reflected only 

 partly over the umbilicus ; the pillar straight, passing without notch or mucro- 

 nation into the reflected basal margin of the aperture ; nacreous layer in this 

 shell covered with a thin non-nacreous layer, which, in its turn, appears to be 

 covered by a delicate epidermis. A marked feature in Gaza is the mucronate 

 pillar, which gives it much the aspect of an Alcadia, while the umbilicus is 

 wholly covered and the shell wholly nacreous. Were it not that I have sev- 

 eral forms agreeing in character, and in these differences, I should have hesi- 

 tated to separate them from Gaza. Such differences, however, are held to have 

 considerable value in littoral forms, and, until we know to the contrary, cannot 

 in abyssal species be held to be valueless. It is probably allied to Gaza, and 

 has a similar operculum. 



Callogaza superba n. s. 



Shell in general features recalling Gaza dcedala Watson, much of whose de- 

 scription would apply with little change to this species. Whorls eight, in the 

 adult roundly shouldered below the suture, rounded at the periphery, some- 

 what flattened on the base, deeply and widely umbilicated, the umbilicus a 

 little more than half covered by a nacreous callus ; first two and a half whorls 

 transparent, not nacreous, very obtuse, the nucleus not prominent ; the next 

 three and a half whorls smooth, except for faintest lines of growth, glassy with 

 the nacre shining through ; the remainder of the shell covered with delicate 

 and distinct lines of growth, sometimes a little more pronounced near the su- 

 ture, and by revolving lines almost too shallow to be called grooves, most promi- 

 nent on the periphery, evanescent on the flattened part of the base and above 

 near the suture ; on the last whorl these are about 0.5 mm. apart ; the region 

 near the suture is almost smooth. Suture very distinct, but not channelled ; 

 umbilicus bordered by an edge from which the flattened base falls away, and 

 with straight walls forming an almost perfect cone ; last whorl contracted just 

 before the reflected lip, which, above, rounds out in advance of its junction 

 with the suture, the last quarter of an inch of which descends on the whorl, 



VOL. IX. — NO. 2. 4 



