CALLIOSTOMA. 373 



couspicuous depression at the umbilical region, which is surrounded 

 by three or four strong lii-ee. Lines of growth fine. Aperture 

 oblique, irregularly pentagonal, smooth, and beautifully i)early. 

 Columella arcuate above, obliquely straightish inferiorly. 

 Alt. 13, diam. maj. 14, min. 12 mill. (Smith.) 



Off the mouth of the Rio de la Plata, 28 fms. 



This beautiful shell is very distinct in form and character from 

 any other in the genus. {Smith.) 



Trochus (Ziziphinus) coppiugeri E. A. Smith, Ann. Mag. Nat. 

 Hist., 5th ser. vi, p. 320 (1880). — Calliostoma coppiugeri Smith, 

 Dall, Proc. U. S. Nat. Mas. 1889, t. xii, f 4. 



I am indebted to Dr. Dall for the privilege of figuring a specimen 

 of this species, taken by the ' Albatross ' of the IT. S. Fish Commis- 

 sion at the original locality, in 10 fms. 



C. ROSKOLUM Dall. PI. 49, figs. 35, 36. 



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 then crenulated by the sculpture, nacreous, 

 obliquely set and subrectangular in form ; sutures appressed, hardly 

 visible exce^it 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 glass. On the 

 upper surface of the whorls are (eight in the last whorl) similar 

 beaded ribs, several of which have rosy threads alternating with 

 crimson ones ; the general rosy hue is clouded darker and lighter 

 alternately, but in an indefinite way. The sculpture of the whole 

 shell is very uniform. Alt. dl, diam. 7 mill. (Dall.) 



This is one of the early finds of Pourtales, lost at Chicago, after- 

 wards refound, and has been known to me for a good many years. 

 It recalls C. macandreoe, from Panama in general form, and is one 

 of a group of small species apparently hitherto undescribed which 



