6 PEOCEEDINGS OF THE NATIONAL MUSEUM. vol. 66 



Pallia! line well marked, about 4 mm. from ventral margin, pallial 

 sinus distinct, acutely pointed. 



The type, Cat. No. 34T866, U.S.KM., measures: Length, 19 mm.; 

 height, 17 mm. ; diameter, 13 mm. It and an odd valve, Cat. No. 

 347867, U.S.N.M. come from the Department of Colonia, Uruguay, 

 nnd were collected and presented by Doctor Felippone. His collec- 

 tion (No. 1580) contains one right valve from the same place. 



This species is entirely different from any hitherto known and will 

 be easy to recognize. Structure, color, form, and other feature of the 

 shell are so superior to the usual Corhicula that they have suggested 

 the specific name. A general pinldsh or salmon tinge pervades the 

 whole shell. The valve in Doctor Felippine's collection is decorti- 

 cated, thus showing the shell color unobscured by the periostracum. 

 It is plainly to be seen that not only the surfaces of the calcareous 

 portion of the shell but the texture of this portion itself is of this 

 color. 



CORBICULA (CYANOCYCLAS) FELIPPONEI, new species. 



Plate 1, figs. 1, 7, 11. 



Shell large, thick, heavy, subcircular in outline, posterior maigin 

 slightly truncated. Beaks eroded, high, located just in front of the 

 middle. Anterior margin sloping slightly from the beaks, then curv- 

 ing regularly into the regularly curved ventral margin which joins 

 the posterior margin in a rounded angle. Posterior dorsal area 

 appearing to be pinched. Posterior dorsal ridge rounded but promi- 

 nent. Sculpture consisting of a number of rude lines of growth, 

 wdth minor lines between them. Growth lines crowded anteriorly 

 and posteriorly and near the ventral margin. Color of exterior 

 blackish brown, with chestnut tints here and there. Color of interior 

 very striking, of various shades of white, flesh-color, pink, lavender, 

 and purple. Cavity of the beaks white, teeth and a broad irregular 

 band round the whole margin pink, flesh color, or lavender ; a broad 

 zone of which the pallial line marks the middle is of various tints of 

 purple. Between the pallial line and the ventral margin are nine 

 or ten purple rays pointing toward the beaks. A broad purple ray 

 extends from near the beak to the upper part of the posterior ad- 

 ductor scar. Cardinal teeth of the usual type but large and thick; 

 between the cardinals and the beginning of the posterior lateral 

 teeth the hinge plate is very broad, somewhat as in Batissa. Lateral 

 teeth very strong, double in the right valve, single in the left, all of 

 them rather short. Anterior laterals of right valve nearly straight, 

 the groove between them narrow, the inner one the stronger, its 

 upper edge undulating and crenulated. Posterior laterals of right 

 valve with a wide groove between them, the inner lateral nearlv 



