ACADEMY OF NATURAL SCIENCES. 189 



apicem lutea, ultra marginem testae projecta ; intus lutea, prope marginem cee- 

 rulescens. 



Long. 1-3, lat. 11, alt. -5. 



Animal unknown, shell sub-elliptical, elevated ; apex sub-central, blunt ; epider- 

 mis reddish brown, yellowish on and near the apex, projecting beyond the margin 

 of the shell ; color internally straw yellow, shading towards the margin into a 

 bluish white. ' 



The above measurements are approximate, making allowance for the epidermis 

 which in the dry specimen is contracted and incurved around the margins to a 

 width of about a tenth of an inch. 



A single specimen, fresh, though without the animal, was found by Dr. Cooper 

 on the shore of Santa Barbara Island. 



No. 994, Mollusca, Survey Cabinet. 



CIECE, Schum. 



S. G. Lioconcha, Morch. 

 C. (L.) Newcombiana, G. 



C. t. tenui, trigono-ventricosa, polita, minute et concentrice striata ; apicibus 

 magnis, subcentralibus ; lunula hand profunda, cordata, margine arata ; colore gil- 

 vo, lineis angulatis, rufis picto ; intus pallida. 



Long. IS, lat. 1-37, alt. -45. 



Shell thin, trigonally ventricose, polished, marked by minute concentric striae ; 

 beaks large, subcentral ; anterior end prominent, narrowly rounded, posterior a 

 little the widest, base convex ; lunule not excavated, bounded by an impressed 

 line ; color yellowish white, variously lined with brown angular lines ; interior 

 whitish ; internal margin smooth ; hinge teeth delicate. 



Hab. two valves, Catalina Island, 120 fms. Dr. Cooper. 



No. 1058, Mollusca, Survey Cabinet. 



The relative length and width of the two specimens is different, the smaller 

 specimen not being so convex at the base as the one measured. 



YOLDIA. 

 Y. Cooperii, G. 



Y. t. tenui, compressiuscula, valde ineequilaterali, antice angusta, postice expan- 

 6a ; umbonibus minutis, per positionem anteriorem excentricis ; epidermide oliva- 

 cea, nitida ; concentrice et confertim lirata ; liris minutis, sub lamellosis ; intus 

 lactea ; cicatricibus muscularibus magnis. 



Long. 1-25, lat. 2-6, alt. -25. 



Shell thin, somewhat compressed, very inequilateral, beaks placed about a third 

 of the length from the anterior end, minute ; anterior end narrow, sub-acuminate, 

 posterior end broadly rounded ; base most prominent just posterior to the middle 

 of the shell; surface sculptured by numerous small concentric ribs, rarely dicho- 

 tomous or anastomosing on the widest part of the shell; these ribs are flat and 

 abruptly truncated on the side nearest the beak, giving the surface, under a glass, 

 the appearance of an overlapping. Epidermis shining, olivaceous j internally a 



