DALL: MOLLUSCA AND BRACHIOPODA. 351 
suture; these are crossed by subequal, fine, sharp, somewhat protractive axial 
threads, at first small and crowded, but becoming more distant, subequidistant, and 
sharp as the whorl grows ; the spirals increase by intercalation, and on the second 
whorl the axial threads begin to fade out, until they are reduced to beadings on 
the spirals between the suture and shoulder, and finally on the last whorl the 
spiral next the suture alone is beaded, and the peripheral major spirals have in- 
creased to six, while on the slightly flattened base there are about eighteen, close- 
set, even, gradually diminishing in size toward the umbilicus, which is bordered by 
a small sulcus, inside of which is a square-topped keel of two threads notching the 
margin of the aperture where they intersect it; inside of this is a twisted funic- 
ular umbilicus with one entering spiral thread on its walls, also ending in a 
small notch at the aperture; mouth rounded except at the notches; outer lip 
sharp, thin, crenulated by the spirals; pillar thin, arcuate, slightly reflected ; 
whorls rounded except where slightly turrited by the shoulder keel; operculum 
thin, brownish, concave, many whorled, the margins of the whorls projecting as 
laminae from the surface externally. Alt. of shell, 17; of last whorl, 13 ; of ap- 
erture, 8.5; max. diam. 15.5; min. diam. of base, 13.5 mm. 
U.S. S. “ Albatross,” station 3413, near the Galapagos Islands, in 1360 fath- 
oms, ooze, bottom temperature 36°F. U.S. N. Mus. 122,959. 
This elegant little shell is well distinguished by its sculpture from any of the 
allied species. It is perhaps not quite mature, and the pillar lip in the fully adult 
shell may be somewhat modified. 
Solariella equatorialis Da t, n. sp. 
Plate 5, figure 11. 
Shell thin, pearly, the nacre shining through the translucent outer coating, and 
a pale yellowish, axially striated, silky periostracum; whorls six, exclusive of the 
(lost) nucleus ; suture distinct, not channelled; whorl in front of it horizontal 
with a fine spiral thread at a short distance, giving a somewhat tabulate effect ; 
somewhat more distant is a second stronger thread at the shoulder, and a similar 
one at the periphery, while a fourth forms the margin of the base against which 
the suture is laid; on the base are four more similar threads, becoming gradually 
more adjacent and feebly beaded or nearly simple, except the fourth, which is dis- 
tinctly, minutely beaded, while a fifth, forming the brink of the large, wide, and 
deep umbilicus, is even more strongly beaded ; axial sculpture of minute, feeble, 
radial wrinkles which at their intersection with the posterior thread crenulate it, 
and on the second and third threads produce, at intervals of about a millimeter, 
sharp, triangular, subspinose nodules ; the entire shell is covered with axial, fine, 
retractive, silky striation ; whorls full, base rounded; umbilicus very deep, funic- 
ular, the walls axially striated; aperture rounded-quadrate, the margins thin; 
pillar oblique, slightly excavated, not callous, slightly expanded ; body and throat 
pearly. Alt. 21; of last whorl, 14; of aperture, 8.5; max. diam. of shell, 19.5 ; 
of umbilicus, 5.5 mm. 
