326 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
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umbilicus imperforate; axial sculpture of very minute elevated, arcuate, radial 
Enes, in harmony with the lines of growth which minutely but distinctly bead the 
keel nearest the suture, but do not affect the others; aperture subquadrate, outer 
lip modified by the sculpture, thin, concavely arcuate behind; body with a thin 
wash of callus; pillar thin, concave, strongly twisted, not reflected, truncate 
anteriorly, so that its junction shows a projecting point in front of a shallow sul- 
cus. Lon. of shell, 4.0; of aperture, 1.5.; max. diam. 3.5 mm. 
U. 8. S. “ Albatross,” station 3431, off Mazatlan, in 995 fathoms, mud, bottom 
temperature 37° F. U.S. N. Mus. 123,034. 
This species is easily distinguished from the preceding by the different sculp- - 
ture, its more elevated form, and the absence of the umbilical perforation. It is 
nearest among described species to the monocingulata of Seguenza, from which it 
may be instantly distinguished by the beaded ante-sutural keel and its somewhat 
broader and shorter conical form. 
Vermetidae. 
PETALOCONCHUS Lzrea. 
Petaloconchus complicatus Datz, N. sp. 
Coil at first closely wound and more or less obliquely bent in conformity with 
its situs, the first few turns with a subcircular section, very irregularly disposed, 
those following with a roughly hexagonal section closely coiled around a barely 
perforate axis, closely coherent to each other and running up to twenty or more 
in number, after which the tube once more becomes erect, with a circular 
section, and a slight dextral twist; aperture circular, often with a series of in- 
ternal concentric lamellae as if the animal had attempted to contract the opening 
by secreting a succession of smaller tubes within it; sculpture irregular; apart 
from incremental lines, there is a longitudinal, irregular, but tolerably smooth ridge 
on the middle of the exposed whorl with strong wrinkles at right angles to it on 
each side but not crossing it. At resting stages there are sometimes angular pro- 
jections of the margin of the temporary aperture; the wrinkles are sometimes 
reticulated by longitudinal subequal threads, which may be entirely wanting on 
other parts of the same individual; the erect portion is nearly smooth except for 
lines of growth; the color is a pale ferruginous brown; the length of the coiled 
portion may be about 16, and of the erect part 27 mm., the tube with a diameter 
at the aperture of 2.3 mm. ‘There is one internal basal lamella and a smaller one 
projecting from the axial wall at about right angles to and a little above the 
former. 
U.S. 5. “ Albatross,” station 3368, near Cocos Island, on dead shells, at a 
depth of 66 fathoms, bottom temperature 58°.4 F. U.S. N. Mus. 123,035. | 
This has somewhat the habit of the typical species of the genus, but is smaller, 
less regular, and with a much smaller axial perforation. 
