DALL: MOLLUSCA AND BRACHIOPODA. 347 
the periphery, and numerous finer, obscure, spiral lirulae over the rest of the sur- 
face; aperture extremely oblique, outer lip produced along the suture, retrac- 
tively arcuate between suture and periphery, produced and patulous at the 
Periphery, thence obliquely arcuate to the base of the pillar; it is everywhere 
Simple, smooth, not reflected, but loaded with a heavy layer of callus, which is also 
Spread evenly and smoothly over the body and about two-thirds of the base; 
pillar extremely short, flattened, produced in a single large, flattened, heavy tooth, 
with a deeply excavated notch between the tooth and the anterior margin of the 
aperture; the callus entirely covers and conceals the umbilical depression if any 
existed. Height, 7.0; of aperture, 3.5 ; max. diam. about 15.0 mm. 
U.S. S. “ Albatross,” station 3396, Gulf of Panama, in 259 fathoms, mud, 
bottom temperature 472.4 F. U.S. N. Mus. 122,954. 
The interior of the shell was once pearly, but has been dulled by decay. It is 
Impossible at present to say whether the broad mass of callus on the base was 
originally opaque white or pearly. 
GAZA Warsox. 
Gaza Watson, Journ. Linn. Soc., 1879, 14, p. 601; Challenger Report, Gastropoda, 
1885, p. 93; type, Gaza daedala Watson, op. cit. 
Gaza rathbuni Darr. 
Plate 2, figure 4; plate 3, figure 6. 
Gaza rathbuni Dall, Bull. Mus. Comp. Zoöl., June, 1889, 18, p. 354; Proc. U. S. 
Nat. Mus., 1889, 12, p. 842, pl. 7, fig. 4 (immature). 
U. 5. 5. “ Albatross,” station 2818, near the Galapagos Islands, in 392 fathoms, 
Sand, bottom temperature 44? F. Also at station 3402, in 421 fathoms, ooze, 
temperature 42°.3, in the same vicinity. U. 8. N. Mus. 199,955. 
The original specimen was immature, not having formed the reflected lip. The 
Species has therefore been refigured from the present material. pn 
An additional note may be made that the nuclear whorls of all the species of 
Caza which I have examined have a membranous consistency, so that when the 
shell has dried the nucleus shrivels up and drops off, leaving a cylindrical perfora- 
tion which is continuous with the umbilicus. 
The dimensions of the adult shell are: alt. 32; of last whorl, 28; of aperture, 
(vertical), 93; max. diam. of base, 45; min. diam. 38 mm. : 
The periostraeum is olivaceous, polished, very thin, and readily dehiscent. In 
atson’s type it had, doubtless, been lost, thus accounting for his observation 
that it was wanting in @, daedala. 
; This genus affords, perhaps, the most exquisite gems of the abyssal shell fauna; 
m shape and iridescence nothing more lovely can be imagined. 
