MUSEUM OF COMPARATIVE ZOOLOGY. 45 



keels a little recurved at their edges, and crossed only by most delicate lines of 

 growth ; base flattened, ornamented with nine angular ribs, the outermost pro- 

 duced somewhat ; umbilicus none, aperture subrectangular, notched by the 

 keels ; pillar simple, somewhat projecting at its anterior end, not callous ; 

 suture appressed, distinct, not channelled. Alt. 8.0. Basal diam. 6.0. Diam. 

 of aperture, 3.0 mm. 



Yucatan Strait, 640 fms. ; Station 2, 805 fms. 



This somewhat resembles a Calliostoma annidatum in miniature, with the 



Calliostoma tiara Watson sp. 



Trochus {Ziziphinus) tiara "Watson, loc. cit., p. 696 (390-1,075 fms.). 



Off Havana, Sigsbee, 450 fms. ; Station 44, 539 fms. ; Station 20, 220 fms. 

 (St. Thomas and Bermuda, Watson, Challenger Exp.) 



The number of these which I have to compare is smaller than of Margarita 

 cegleis, but the variations are as numerous as the individuals, and there are 

 specimens with an impervious base, while others indicate a chink in the um- 

 bilical region. The sculpture is tolerably constant, and the elevated shape 

 much more so than in the Margaritas. 



Calliostoma Bairdii Verrill and Smith. 



C. Bairdii Verrill and Smith, Am. Journ. Sci., loc. cit., p. 396, Nov. 1880. 

 C. Psyche Dall (not described), Bull. M. C. Zoiil., V., p. 61, July, 1878. 



This lovely species was first found by Pourtales in 100 to 200 fms. along the 

 Florida reefs ; it seems to vary from 80 to 350 fms. in its habitat. The orig- 

 inal specimens were burned at Chicago ; others were subsequently collected, 

 and more lately it has been found by the United States Fish Commission in 

 deep water off Newport, R. I. It strongly recalls some of the European forms. 



Calliostoma roseolum n. 8. 



Shell acute conical, eight-whorled ; the first five whorls flattened, the last 

 three somewhat rounded ; periphery of last whorl gently rounded to meet the 

 rather flattened base ; umbilicus none ; pillar short, straight, ending in a 

 slight knob inside the margin of the aperture, which is thin, crenulated by the 

 sculpture, nacreous, obliquely set and suljrectangular in form ; sutures ap- 

 pressed, hardly visible except in the last three whorls ; color delicate rosy, 

 nucleus smooth and white ; the base with about twelve equal revolving ribs 

 consisting of successive rounded nodules, of even size, somewhat like strings of 

 beads ; the first, third, and fifth ribs, counting from the pillar, show every 

 third bead crimson, the others white ; the other basal ribs have the rosy color 

 of the shell, but in the seventh, ninth, and eleventh, each alternate or each 

 third bead has a deeper crimson tint, though this is hardly visible without a 



