GAZA. 157 



very distinct, but not channelled ; umbilicus bordered by an edge 

 from which the flattened base falls away, and the straight walls 

 forming an almost perfect cone ; the 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, giving the aperture a downward look ; aper- 

 ture oblique above, arching more nearly to a perpendicular below, 

 smoothly, evenly reflected and thickened from the pillar to the 

 suture, with an internal channel behind the thickening ; pillar 

 callous above, thinly and unevenly reflected half-way across the 

 umbilicus, gently and very obliquely descending and smoothly 

 passing into the basal part of the lip. The interior of the aperture, 

 the lip, the umbilical callus, and a slight wash near the sutural 

 junction, brilliantly nacreous; base and body whorl within the 

 mouth not so; upper surface of shell distinctly tinted with fawn 

 color, base waxen white, the nacre perceptible through the thinner 

 portions. Alt. 24*0 ; maj. diam. 35'5 mill; of umbilicus, 8'0; of 

 aperture, lo'O mill. Defl. about 100. (Dall.) 

 Off Montserrat, Santa Cruz, Barbados, and in the Gulf between 

 Mississippi delta and Cedar Keys, Fla., 209 to 324 fins. 



Callogaza superba DALL, Bull. Mus. Cornp. Zool. ix, p. 49, 1881 ; 

 Gaza superba DALL, I.e. xviii, p. 354, t. 22, f. 4, 4a. 



Dr. Dall writes of this species: I included this species with the 

 subgenus Callogaza in my preliminary paper, but the receipt of 

 more specimens from the U. S. Fish Commission dredgings leads 

 me to doubt whether the umbilicus always remains uncovered, and 

 though I have seen no specimens in which it is wholly closed, yet I 

 suspect it becomes so at times. An adult specimen measures 40 

 mill, wide by 32 high, and this appears to be about the average of 

 the species. 



G. RATHBUNI Dall. 



Another species of about the same size (38 x 24 mill.), G. rath- 

 buni Dall, which differs from G. superba in being more depressed, 

 with stronger spiral grooving, a slightly smaller umbilicus, and 

 more flattened over the sutures, has since turned up among the 

 ' Albatross ' collections, dredged in the Pacific, in 392 fins., sand, 

 near the Galapagos Islands. (Dall, Bull. Mus. Comp. Zool. xviii, 

 p. 354, foot note.) 



