jRT. 15 MOLLUSKS OF THE GENUS COEBICULA MARSHALL. 5 



sliining. General color light olive green, the margin salmon color, 

 posterior area with three broad rays of salmon color and three rays 

 of greenish. Faint indication of narrow dark rays elsewhere. In- 

 terior of the shell purplish gray with whitish margin, the posterior 

 end with three broad rays of purple and three of salmon. Cardinal 

 teeth widely divergent, more plainly bifid than in most CorUcula. 

 Anterior laterals of right valve rather long, plainly curved at the 

 lower end, posterior laterals short, high at its upper end. Pallial 

 line and sinus fairly well marked. 



The type. Cat. No. 347862, U.S.N.M., measures : Length, 11 mm. ; 

 height, 9 mm. ; diameter, 4: mm. It was presented by Doctor Felip- 

 pone, who collected it in the Department of Paysandu, Uruguay, 

 It is a. young specimen, but was selected for type as it is the only one 

 of the lot received which is nearly j^erfect. The species becomes much 

 larger — another specimen measuring: Length, 20 mm.; height, IT 

 mm.; diameter, 9 mm. Its nearest relative is limosa Maton, from 

 ^\•hich it differs slightly in form and greatly in coloring. 



CORBICULA (CYANOCYCLAS) EXQUISITA, new species. 



Plate 1, figs. 9, 10, 12. 



Shell thin, very inflated, cordate, beaks turning forward, dorsal 

 line lightly arched, posterior margin nearly squarely truncate, dis- 

 tinctly angled above, obscurely angled below. Anterior margin 

 rounded, the anterior portion of the shell advancing, giving the shell 

 a pouting appearance. Ventral margin rounded, posterior ridge 

 high, rounded, posterior area very broad, obscurely, cordately sulcate 

 beaks a little back of the middle of the dorsal line, eroded but retain- 

 ing traces of rather heavy concentric, raised lines. Color very light 

 chestnut, uniform, but sparingly rayed with very narrow darker 

 chestnut lines. Posterior area with three broad radiating livid stripes. 

 Beaks with a pinkish tinge. Sculpture consisting of numerous con- 

 centric raised lines, which are stronger anteriorly and crowded and 

 nuich finer posteriorly. Periostracum thin, somewhat shining. Lig- 

 ament very short, close to the beaks. Interior of shell pinkish every- 

 v.'here. Anterior cardinal tooth of right valve very small, triangular, 

 A ery sharp, the other two fairly strong, and both of them markedly 

 bifid. Laterals in this valve double, the inner ones crenulate on edge 

 and coarsely striate on upper surface. In left valve the first and 

 second cardinals are fairly strong and slightly bifid, the third cardi- 

 nal thin, high, platelike, pointed. Anterior lateral crenulated, 

 strongly striate on its outer face and with oblique shallow grooves 

 cutting across the striae. Posterior lateral remote from beaks very 

 high, nearly pointed at its middle, obscurely crenulated and striati»d. 



