: 167 
riorly, the latter half nearly straight; cream-white, often yellow- 
ish toward the:mouth, shining where not eroded, earlier portion 
usually dull and chalky because of erosion; growth-lines fine, ir- 
regular, distinct, rarely an encircling groove due to repaired frac- 
ture; at the apex there are longitudinal, low, rounded, incon- 
spicuous threads, of which 7 or 8 are more prominent and 3 to 6 
in each interspace are less prominent; these die out, and fine, 
superficial strise appear, visible under the glass and continued to 
the mouth of the shell, 7 or 8 per millimeter of circumference; 
aperture simple, circular, mouth slightly oblique. Two specimens 
measure: length 64.5, diam. of aperture 5.3, of apex 1.5, at mid- 
dle 4.6, height of arch from chord 2.5, mm.; length 64, diam. of 
aperture 4.7, of apex 1.4, at middle 4.2, height of arch from chord 
3 mm.’’—Raymond, Nautilus 17:123. 
Off Santa Monica, and San Diego, Cal. 
2426 Pleurotoma (Genota) Stearnsiana 
‘Shell broadly fusiform, spire acute, outline of spire moderate- 
ly convex; whorls 8%, convex anteriorly, slightly concave near 
the suture, the margin at the suture strongly appressed; suture 
distinct; aperture longer than the spire; color orange to cream, 
a broad, spiral, brown band below the suture and 9 or 10 narrow, 
clearly-defined bands on the last whorl, 1 or 2 of these are also 
visible on the spire, bands nearly as wide as the lighter inter- 
spaces; interior of aperture yellowish, lighter within and spotted 
with brown on the outer lip by the external bands; first 2 whorls 
smooth, later whorls with numerovs revolving threads, closely 
beaded on the spire by incremental lines which follow the outline 
of the lip, threads not beaded below the periphery of the last 
whorl, but roughened by the growth-lines and somewhat coarser 
anteriorly; aperture, rather narrow; posterior sinus shallow, 
rounded; lip acute, produced below the sinus, canal wide; pillar 
solid, somewhat curved, obliquely truncate below. Operculum 
normal. Long. of shell 30.5, of aperture and canal 17, of body- 
whorl 23 mm; max. diam. 13 mm. Divergence 50 degrees. An 
extremely old specimen which shows a thickening of the pillar 
like an obscure fold, measures: long. of shell 41.5, of aperture 
and canal 22.5, of body-whorl 29.5 mm.; max. diam. 18 mm. 
Divergence 49 degrees.’’ Raymond, Nautilus 18:1. 
Off San Diego, Cal., in 25-30 fms.—Catalina Island, 30-40 fms. 
Named in houor of Dr. Robert Edwards Carter Stearns. 
2427 Pleurotoma (Antiplanes) Catalinz 
“Shell sinistral, thin, elongated, slender, whorls 10-11; color 
light, pinkish brown, without bands, interior of aperture a little 
lighter; upper whorls more or less chalky; nucleus smooth, in- 
flated; suture deeply impressed; sculptured by fine incremental 
lines and in the last whorl a few obscure, spiral striations, mostly 
below the periphery; anal fasciole traceable on the spire as a 
flattened or obscurely grooved band; aperture narrow; canal wide 
and short; pillar nearly straight, with a well-defined callus 
obliquely truncate below; outer lip produced, deeply emarginate 
near the sutural margin of the whorl. Long. of shell 27, of aper- 
ture and canal 10.5, max. diam. 7.6 mm. Divergence 20 degrees.”’ 
—Raymond, Nautilus, 18:2. 
Off Catalina Island, in 125 fms.—Off San Diego, Cal., in 50- 
106 fms. 
2428 Pleurotoma (Genota) Riversiana 
Raymont, Nautilus 18:14, Pliocene of. Santa Monica, Cal. 
named in honor of J. J. Rivers. 
