106 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
the penultimate whorl. Intercostal spaces about four times as wide as 
the ribs, marked by numerous, fine, irregular wavy markings, which 
give a watered-silk effect. Suture moderately constricted. Periphery well- 
rounded. Base of last whorl moderately long, concaved in the middle, 
having a slender fasciole at its anterior termination, marked by the feeble 
continuations of the axial ribs and the same wavy sculpture observed in 
the intercostal spaces of the spire. Aperture large, decidedly effuse, feebly 
channeled posteriorly; outer lip very thick and effuse, reinforced immedi¬ 
ately behind the edge by a thick varix; inner lip slender, curved and 
appressed at the base; parietal wall covered with a thick callus which 
renders the peritreme complete. Length, 2.8; diameter, 1.2 mm. 
(Bartsch.) 
Type in United States National Museum, No. 226456. Type locality, 
off South Coronado Island. 
Range. Known only from type locality. 
Rissoina californica Bartsch, 1915 
Plate 83, fig. 1 
Proceedings of the United States Natiotial Museum , 49:55; PI. 33, fig. 1. 
Shell very minute, elongate-conic, semitranslucent, yellowish-white. 
Nuclear whorls 27, well-rounded, smooth. Post-nuclear turns well-rounded, 
marked by strong, decidedly protective, slightly sinuous, axial ribs which 
are about half as wide as the spaces that separate them. Of these ribs, 14 
occur upon the first, and 16 upon the remaining turns. These ribs extend 
strongly from the summit to the sutures on each turn and are not at all 
constricted below the summit. The intercostal spaces are deep, well- 
rounded, and smooth. Suture strongly impressed. Periphery of the last 
whorl well-rounded, marked by the continuation of the axial ribs which 
extend over the somewhat prolonged base to the umbilical chink where 
they become slightly fused on the tumid area surrounding the umbilical 
region. Aperture oval; slightly channeled at the posterior angle and at 
the junction of the outer lip and the columella; outer lip reinforced 
immediately behind the edge by a thick callus; columella strongly reflected 
over and appressed to the base; parietal wall covered with a thick callus 
which renders tlie peritreme complete. Length, 2.8; diameter, 1.2 mm. 
(Bartsch.) 
Type in United States National Museum, No. 271644. Type locality, 
off South Coronado Island. 
Range. Catalina Island to South Coronado Island. 
[ 708 ] 
