532 A, E. Verrill— Catalogue of Marine Mollusca. 
ond, midway between the suture and periphery, is the largest, most 
prominent, and most constantly present; below this there may be 
two or three evident carinz, or these may be absent, or replaced by 
several fine, spiral cinguli. Transverse, low ribs or undulations may 
be more or less distinct on all the whorls, but more frequently are 
present on the upper whorls, and obsolete, or nearly so, on the 
lower ones. 
These varieties pass into one another by various intermediate forms. 
Var. carinata, nov. 
This form may prove to be a distinct species. It has the form and 
the large umbilicus of J. obscura, but its strong, spiral carine and 
the distinct spiral carina around the umbilicus cause it to resemble 
Margarita cinerea. The body-whorl has a distinct subsutural carina 
and three well-separated, strong, raised carinz below it, the fourth 
forming a peripheral keel ; sometimes smaller intermediate ones occur 
between the third and fourth, and two or more smaller ones below 
the periphery; in some examples distinct mcised spiral lines cover 
the whole of the base and inner surface of the umbilicus, while a 
strongly marked carina, with a deeper groove each side of it, defines 
the umbilicus. Transverse undulations are usually well-marked on 
the upper whorls, and sometimes on the base. There are no lamel- 
lose lines of growth, so characteristic of JZ. cinerea; and the umbili- 
cus is much larger than in the latter. 
Off Martha’s Vineyard, stations 997, 1032, 1038, in 146 to 335 
fathoms, 1881. 
Cyclostrema Dalli Verrill, sp. nov. 
Cyclostrema trochoides Verrill, Proc. U.S. Nat. Mus., iii, p. 378, 1880 (non Friele, Sars). 
PLATE LVII, FIGURE 39. 
Shell small, pale, trochiform, with about three and a half whorls, 
the apical whorl a little prominent, visible in a side-view ; whorls 
rapidly enlarging, well-rounded, the body-whorl ventricose; suture 
deeply impressed. Aperture nearly circnlar; lip with a slight angle 
anteriorly ; columella evenly curved. Umbilicus entirely closed, or 
represented by a very narrow chink. Spiral, incised lines, seven or 
eight in number, cover the base of the shell and the umbilical depres- 
sion; shell elsewhere nearly smooth, but covered with very fine stria- 
tions, or lines of growth, which give the surface a dull appearance, 
the freshest specimens having only a slight luster. Coler yellowish 
white. 
