410 



CALLIOSTOMA-EUTROCHUS. 



aperture on the last whorl. Base with two strong nodulous spirals 

 separated by a deep interspace, the inner one forming the umbilical 

 margin ; outside of these U)-20 fine flattened spiral threads, wiih 

 about equal interspaces, reaching to the periphery and hardly 

 ruffled by the incremental lines. Radiating sculpture much like 

 that of C. tiara, of numerous, on the earlier whorls strong, slightly 

 elevated oblique threads, extending clear across the whorls and 

 reticulating the spirals; these radii gruw fainter and finally on the 

 last whorl nearly disappear; on the base there are only faint 

 flexuous incremental lines. Umbilicus narrow, its walls flexuous, 

 yellow. Aperture squarish, the pillar little concave, not toothed, 

 margin thin and simple. Upper surface of whorls excei)t the 

 sculpture flattened; suture distinct, not channelled. Operculum 

 horny, multispiral. Alt, 9-5 ; diam. 8 mill. (Dall.) 



Off Havana, in 174 fms. 



Calliostoma (Eutrochns) cincteMuni Dall, " Blake " Gasteropoda, 

 p. 372, t. 32, f 1,4. 



Soft ])arts whitish, foot short, pointed behind, muzzle rounded, 

 gill simple, anus prolonged into a long free papilla, eyes large; 

 tentacles long and stout, without frontal lobes ; epipodium with a 

 large anterior lobe, and four cirri all anterior to the operculum and 

 about of equal size. Jaws separate, squarish, composed of small 

 horny obliquely set rods, whose lozenge-shaped end-sections reticu- 

 late the surface under the microscope. 



The dentition is peculiar. The rachidian and (on each side) five 

 laterals have broad simple bases with a j)ear-shaped outline ; the 

 cusps, which might be compared to the stem of the pear bent over, 

 are extremely narrow and long and symmetrically serrate on each 

 side with 4-6 serrations. The major uncinus is stout and has a 

 large four-toothed ovate cusp ; there are about twenty more slender 

 uncini with scythe-like cusps serrate on the outer edge ; outside of 

 these are two or three of a flat form, like a section of a palm-leaf 

 fan from handle to margin with four riblets, and the distal edge 

 with three or more indentations. Under pressure these uncini have 

 a tendency to split up lengthwise, beginning at the indentations. 

 They are flat and smooth, thinner towards the distal end, and have 

 no distinct shaft. 



This interesting species looks at the first glance as if the ex- 

 cavated space between the peripheral cinguli was fasciolar, like 

 that of Eucasta, but a more careful inspection shows that there is 



