CLASS GASTROPODA 
85 
aperture white. Surface polished, marked by fine line of growth only. 
Surface feebly impressed. Periphery of the last whorl angulated. Base 
short, well-rounded. Aperture broadly oval; posterior angle acute; outer 
lip thin, curved and slightly patulose; inner lip curved and revolute, 
almost covering the narrow umbilicus. Length, 3.1; diameter, 1.2 mm. 
(Bartsch.) 
Type in United States National Museum, No. 127544. Type locality, 
San Hipolite Point, Lower California. 
Range. San Diego, California, to San Hipolite Point, Lower Cali¬ 
fornia. 
Family PYRAMIDELLIDAE 
Genus PYRAMIDELLA Lamarck s.s. 
Shell of many whorls, turreted, umbilicated; columella with three 
fold; outer lip usually re-enforced within, at regular intervals, by spiral 
lamellar thickenings. The sculpture consists of mere lines of growth and 
very fine spiral striations. (Bartsch.) 
Type. Trochus dolabratus Linnaeus. 
Distribution. World-wide, from low water to 90 fathoms. Fos¬ 
sil : Cretaceous. 
Subgenus Longchaeus Morch, 1875 
Pyramidella adamsi Carpenter, 1864 
Supplementary Report, British Association for the Advancement of Science, 546. 
Bulletin 68, United States National Museum, 21; PI. 1, figs. 6, 6a, 1909. 
Shell elongate-conic, early whorls white, later ones diversely varie¬ 
gated frequently dark brown on the later turns. It is this striking 
variegated color pattern which at once distinguishes this species from 
the other west American forms. The spaces between the sutures are 
crossed by light areas, which are vertical in the middle, bending sud¬ 
denly forward at the periphery and the summit, thus forming ] -shaped 
areas. The space immediately below the peripheral sulcus, but with retrac¬ 
tive slant. The space between these light areas, near the summit, forms a 
series of elongated dark spots. The varices which are disposed at regular 
intervals are chestnut-brown, preceded usually by a band of white. Posterior 
half of the base light chestnut-brown; anterior white. Nuclear whorls 
small, two, forming a planorboid spire whose axis is at right angles to that 
of the succeeding turns, in the first of which it is about one-half immersed. 
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