110 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
pillar scarcely attached to the shell. Length, 4^5; diam., 1 -/$ mm. 
( Binney.) 
Type in British Museum? Type locality, San Diego, California. 
Range. Santa Barbara to San Diego and San Martin Island, Cali¬ 
fornia. 
Family SYNCERATIDAE 
Genus SYNCERA Gray, 1821 (Assiminea) 
Shell conic, usually strong. Nuclear whorl smooth, the rest of the shell 
marked by lines of growth and fine spiral striations only. Outer lip simple; 
inner lip continuing over the base as a thick parietal callus. Operculum 
subspiral, thin, horny. (Bartsch.) 
Type. Syncera hepatica Gray, equals Assiminea gray ana Leach. The 
synceras are littoral forms, frequently inhabiting the brackish reaches of 
our coast. 
Distribution. West coast of America, Europe. 
Syncera translucens Carpenter, 1864 
Supplementary Report, British Association for the Advancement of Science, 613. 
Proceedings of the California Academy of Sciences, 3:219. Proceedings of the 
United States National Museum, 58:164; PI. 12, fig. 7. 
J.t. Barleeiae subtenui simili sed tenuiore, tumidiore; cornea, pallide 
fulva, laevi, nitente, satis diaphana; anfr. nucl. normalibus, apice sub- 
mamillato; norm. iv. subconvexis, suturis distinctis; basi rotundata, haud 
umbilicata; apertura ovata, peritremati vix continuo; labro acuto; labio 
appresso, regione umbilicari parum calloso. (Carpenter.) 
Shell broadly ovate, light brown. Nuclear whorls not differentiated 
from the remaining turns, well-rounded. Post-nuclear whorls strongly 
rounded, very narrowly shouldered at the summit, marked by decidedly 
retractively curved axial lines of growth, and exceedingly fine microscopic 
spiral striations. Suture strongly impressed. Periphery of the last whorl 
well-rounded. Base inflated, well-rounded. Aperture subcircular; pos¬ 
terior angle obtuse; outer lip thin; inner lip very strongly curved, thick, 
reflected over and appressed to the base; parietal wall covered with a thick 
callus which fuses with the reflected inner lip and forms a decided callosity 
over the umbilical region. Operculum typical. Altitude, 3; diameter, 1.9 
mm. (Bartsch.) 
Type. The specimen figured and described is in the United States 
National Museum, No. 271483. Type locality, San Diego, California, in 
shell washings. 
Range. Vancouver Island to Lower California. 
