DALL: MOLLUSCA AND BRACHIOPODA. 289 
aud protractive axial ribs which extend from the suture to the canal except over 
the last half of the last whorl; the constriction which indicates the anal fasciole 
gives the posterior edge of the whorl a marginate appearance, but does not inter- 
rupt the ribs, which are very prominent in front of the fasciole at the shoulder ; 
the whole surface is evenly sculptured by strongly incised, almost channelled lines, 
with wider, flat, strap-like interspaces ; near the canal these become narrower and 
cord-like and the channels wider, diminishing again toward the end of the canal; 
the spiral sculpture does not nodulate the ribs, but is minutely crenulated on the 
eminences by fine, even, incremental lines; aperture short, wide, with a deep — 
rounded anal sulcus next the suture, a thin and much produced outer lip, a short, 
slightly recurved, flaring canal, an arcuate callous pillar, white and smooth, with 
a conspicuous nodule on the body between the sulcus and the suture; operculum 
wanting. lLon., 14; of last whorl, 8; of aperture, 5.5; max. diam. 6 mm. 
U.S. 5S. ‘ Albatross,” station 3391, in the Gulf of Panama, 153 fathoms, mud, 
bottom temperature 55°.8 F. U.S. N. Mus. 128,104. 
The species was also dredged at station 2804, in Panama Bay, in 47 fathoms, 
mud, bottom temperature 64° F. U.S. N. Mus. 122,771. 
The first half of the last whorl in the adult ends in a node or varix, indicating 
a previous resting stage with developed outer lip; beyond this the whorl is desti- 
tute of ribs. . 
Clathurella plicatella Datt, n. sp. 
Shell very small, acute, eight-whorled, flesh color or pinkish white, polished; 
nucleus turbinate, blunt, polished, smooth, of about two whorls; subsequent 
whorls axially sculptured with (on the last whorl behind the node) ten sharp, 
more or less sigmoid, slightly protractive ribs extending from the suture to the 
canal, or on the spire from suture to suture, with wider interspaces; suture 
appressed ; in front of it is a very slight constriction corresponding to an anal 
fasciole, though no actual fasciole is visible; aperture moderate, anal sulcus large 
for the size of the shell, rounded and deep; lip in front of it rounded and pro- 
duced; on the body a small mass of callus limits the posterior edge of the sulcus ; 
the body is smooth and callous, the enamel extending upon the pillar, which is 
short and attenuated; canal short, recurved, on the back finely, sharply, spirally 
striated, but these striae do not extend over the rotundity of the whorl. Length 
of shell, 7.0; of last whorl, 3.5; of aperture, 2.5; max. diam. 2.5 mm. 
U.S. S. “ Albatross,” station 2799, in Panama Bay, in 294 fathoms, mud. 
This pretty little species is a typical Clathurella. 
GLYPHOSTOMA Gasp. 
Glyphostoma immaculata Da tt, n. sp. 
Plate 1, figure 9. 
Shell small, white; with a faint brownish or pinkish flush on the last whorl 
brilliantly polished and with no perceptible periostracum or operculum; nucleus 
VOL. XLIII. — NO. 6 19 
