14 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
wider than the rest. Aperture ovate, feebly channeled anteriorly. Posterior 
angle acute; outer lip thin at the edge; columella decidedly curved, oblique, 
strongly reflected over the reinforcing base; parietal wall covered with a 
thick callus. Length, 6.2; diameter, 2.8 mm. (Bartsch.) 
Type in United States National Museum, No. 203676. Type locality, 
Postpliocene of Santa Barbara, California. 
Range. Known only from the type locality. 
Alabina tenuisculpta Carpenter, 1864 
Plate 96, fig. 6 
Supplementary Report, British Association for the Advancement of Science. Pro¬ 
ceedings of the United States National Museum, 39:415. Proceedings of the 
California Academy of Sciences, 3:216. 
M. t. tenui, regulariter-turrita, fusco-cinerea; anfr. nucl. laevibus, nor- 
malibus, apice acuto; norm. viii. rotundatis, suturis impressis; lirulis 
spiralibus haud extantibus, plus minusve distantibus, irregularibus cincta, 
quarum anfr. primis duae anticae majores; lirulis circa basim rotundatam 
obtusis, subregularibus; rugulis increment irregularibus, interdum decus- 
santibus; apertura subrotundata, peritremati haud continua; labro acuto, 
postice flexuoso; labio tenui. Long., 0.28; long, spir., 0.18; lat., 0.10 poll. 
(Carpenter.) 
Shell acicular, light chestnut brown. Nuclear whorls very small, two 
and one-half, increasing regularly in size, well-rounded. Post-nuclear 
whorls with a strong, very wide, sloping shoulder which extends over the 
posterior half of the whorls between the sutures; and is bounded at the 
summit by a slender spiral thread. The first five post-nuclear turns have a 
strong, median, spiral cord and a second as strong as the median, about 
halfway between these two; a slender spiral thread can be seen on the third 
to the sixth whorl. On the last three whorls the median cord is almost 
completely lost, while the one above the sutural line retains its strength. 
On these three whorls additional fine spiral lines make their appearance. 
The axial sculpture consists of fine lines of growth only. Sutures weakly 
channeled. Periphery and base of the last whorl well-rounded, marked by 
eight subequal and unequally spaced, spiral keels and fine lines of growth. 
The space immediately surrounding the umbilical area has no spiral 
sculpture. Aperture broadly ovate; posterior angle obtuse; outer lip thin ; 
columella slender, decidedly curved and slightly reflected over the narrow 
umbilicus; parietal wall glazed with a thin callus. (Bartsch.) 
Type in United States National Museum, No. 40933. San Diego, Cali¬ 
fornia. 
Range. San Pedro, California, to Magdalena Bay, Lower California. 
Described as Mesalia tenuisculpta. 
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