366 PROCEEDINGS OF THE ACADEMY OP [April, 



Toula has figured and described this species, but by oversight he 

 used a specific name already employed on a previous page of the same 

 paper. 



OSTREIDiE. 



Ostrea gatunensis n. sp. PL XXIX. figs. 1, 2. 



Ostrea spec. ind. and Ostrea aff. vespertina Conr., Toula, Jahrb., p. 710. PI. 

 26, fig. 1; PI. 28, fig. 14. 



A short oval oyster, the convex valve with coarsely, radially 

 corrugated exterior, the ruga? rarely divaricating, and with a few 

 decumbent spines. The rather short beak is bent at an angle of about 

 45 degrees with the long axis of the shell. Inside there is a rather 

 short ligament area, the wide valve-margin adjacent to it being 

 sculptured with strong, close, transverse, irregular wrinkles. The 

 margins are elsewhere simple. Cavity of the valve not deep, and not 

 in the least excavating the beak. 



Length 103, width 72 mm. 



Toula (/. c.) mentions an oyster near vespertina Conrad which is 

 probably the young of this species and of his undetermined Ostrea. 



The interior reminds one somewhat of 0. iridescens Brod., but that 

 has a deep excavation under the beak, among other differences. It 

 stands extremely close to the recent Indo-Pacific 0. hyotis (L.). 



Part of a valve of a very narrow, strongly convex and very peculiar 

 oyster was also found at Gatun. 



CARDIID^E 



Cardium (Trachycardium) stiriatum n. sp. PI. XXVIII. fig. 11. 



Cardium spec, vielleicht eine neue Art, Toula, Jahrb., p. 721, PI. 27, fig. 5; 

 , PL 28, fig. 15«, b. 



The shell is rather thick, very plump, much higher than long, nearly 



equilateral, the posterior end a little straightened. Beaks median, 



the incurved tip concealed by the reflexed hinge-margin. Sculpture of 



30 radial ribs. At the two ends these ribs bear strongly projecting, 



drop-shaped tubercles. In the median part of the valve the ribs lean 



posteriorly, and have a narrow tuberculate cord superposed on the 



posterior side of each, the tubercles elongated parallel to the cord in 



the median ribs, oblique or twisted on it, on the lateral ribs. The 



interstices are not very deep at the ends, but in the median moiety 



of the valve they are narrow and very deeply cut, overhung by the 



high side of the rib. The middle of each rib, anterior of the tuberculate 



ridge, bears one or several low cords, and the anterior slope has some 



fine, irregular, transverse striae. Teeth strong, margin deeply fluted 



