250 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. XXXIY. 
which in some cases are nearly straight, in others curved toward the 
preceding whorl until they may even touch it;-aperture ovate, canal 
long, slender, shghtly recurved. Height, 19.5; of last whorl (with- 
out the spines), 14.5; of aperture and canal, 11.5; maximum diam- 
Guise, OLD) wav. 
Type.—Cat. No. 110648, U.S.N.M. Dredged by Professor Kelsey 
off the entrance to San Diego Harbor in 20 fathoms mud, and at his 
request named in honor of Dr. Charles S. Bentley, resident naturalist 
of the San Diego Biological Station. 
This is nearest to B. avalonensis Dall, but is more slender, with 
one or two more varices to the whorl, and is a more elegant shell. 
There aré faint indications of spiral lineation, coarser toward the 
periphery and finer near the angle of the shoulder. From the varia- 
tion in other species of Boreotrophon I conclude that the curvature 
of the spines is only an individual character, though the extremes 
are strongly. contrasted. 
Genus COLUMBELLA Lamarek. 
Subgenus ANACHIS Adams. 
ANACHIS PETRAVIS, new species. 
Shell minute, blunt, solid, varicolored, chiefly purplish or flesh 
color, but distributed much like the colors on Amphissa versicolor, . 
either solid or in pattern; whorls about six, the nucleus including 
two of these which are smooth, polished, swollen, and apically blunt; 
suture distinct, appressed, the whorl in front of it (the last whorl) 
shghtly constricted; sculpture of (on the last whorl about 16) small, 
subequal, rounded, shghtly flexuous ribs, distally protractive, and 
with narrower, microscopically faintly spirally striated interspaces; 
the last whorl terminates in a pale-colored thickening, or indistinct 
varix; aperture and canal very short and wide; outer lp internally 
with a few indistinct lire; pillar smooth, obliquely attenuated in. 
front. Height, 4.5; last whorl, 2.0; aperture, 1.4; maximum diam- 
eter, 1.7 mm. | 
Type.—Cat, No. 110645, U.S.N.M. Under stones at Bird Rock, 
off San Diego, California. IF. W. Kelsey. 
This species, in miniature, is extremely similar to C. (Anachis) 
minima Arnold, from the Pleistocene of San Pedro, California. 
Arnold’s name being several times preoccupied, I would substitute 
ore Ike CO, (-4l5)) GOUGH. 
Genus OPALIA Adams. 
OPALIA (DENTISCALA) MAZATLANICA, new species. 
Shell small, slender, white, the porcellanous layer subtranslucent, 
the surface layer very thin opaque white; nucleus smooth, of about 
a whorl and a half, blunt, and followed by five or six sculptured 
