278 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
plication at the proximal end of the pillar; axis impervious, canal short, wide, 
deep, slightly recurved with a fairly well-marked fasciole. Lon. of shell, 29.0; of 
last whorl, 16.5; of aperture, 12.0; max. diam. 9.0 mm. 
U. S. S. “ Albatross,” station 2931, off Los Coronados Islands, California, in 
34 fathoms, sand, bottom temperature 56° F, U.S. N. Mus. 110,608. 
This is nearest B. dalli Arnold, but of a different color, more slender, and on 
the last whorl has the flattened fasciolar area very much wider. The fold on the 
pillar is easily visible. 
PLEUROTOMELLA VERRILL. 
Pleurotomella (Gymnobela) agonia Darr. 
Plate 1, figure 6. 
Pleurotomella ( G'ymnobela) agonia Dall, Proc. U. S. Nat: Mus., 1889, 12, p. 807, pl. 6, 
fig. 4. 
Shell large, thin, chalky, with a pale straw-colored periostracum ; form biconic, 
with a presumably blunt, eroded apex and about seven whorls ; suture distinct, 
minutely channelled ; the margin in front of the suture is turgid and pinched up 
into numerous short, narrow, obliquely retractive small folds with wider interspaces 
and rounded summits; these become obsolete on the last whorl; there are about 
twenty-one on the penultimate whorl, and they do not cross the anal fasciole which 
is gently excavated ; on the shoulder of the whorl are a series of lunate projections 
corresponding to the anal sulci (about nineteen on the penult whorl) less distinct 
and prominent than the sutural folds but larger: the whole surface is spirally 
sculptured with small low flattish ridges finer and closer on each side of the shoulder 
but elsewhere subequal and nearly equidistant, with subequal interspaces which 
become somewhat wider near the canal; there are also numerous very fine spiral 
striae and lines of growth forming a microscopic obscure reticulation; base 
rounded, attenuate in front; outer lip (defective) thin, simple, with a wide shallow 
anal suleus at the shoulder; body and pillar slightly callous, with the appearance 
(which may be pathological) of an internal spiral ridge on the pillar not visible 
from the aperture ; pillar straight, very obliquely truncate and twisted in front; 
canal moderately wide, not recurved. ‘Lon. of (decollate) shell, 25; of last whorl, 
18.5; of aperture, 14; max. diam. 12 mm. 
U. S. 8. “ Albatross,” station 2808, near the Galapagos Islands, in 634 fath- 
oms, coral sand, bottom temperature 40° F. U.S. N. Mus. 96,493, Also at 
2807, in 812 fathoms, ooze, temperature 38°. 4. 
Pleurotomella (Gymnobela) agonia var. altina Darr, nov. 
Plate 14, figure 9. 
Shell large, thin, pinkish brown, biconic, spire slightly longer than the aperture 
with seven well-rounded whorls in addition to the (lost) nucleus; suture dis“ 
