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 striae 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 numerous 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; ma.<. 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 4 9 degrees." Raymond, Nautilus 18:1. 



Off San Diego, Cal., in 25-30 fms. — Catalina Island, 30-40 fms. 



Named in honor of Dr. Robert Edwards Carter Stearns. 



2427 Pleurotoma (Antiplanes) Catalinje 



"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 ptriations, 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 «e]i-deuued callus 

 obliquely truncate below; outer lip produced, deeply emargiuate 

 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. 



