FREE INSTITUTE OF SCIENCE 



IO6? 



TERTIARY FAUNA OF FLORIDA 



existence of the following species in our Miocene, the genus not being known 

 from Atlantic waters and hitherto represented only by its type, which occurs 

 in the Pleistocene of San Pedro, California.. 



Cooperella Carpenter! n. sp. 

 PLATE 49, FIGURE 8. 



Miocene of Petersburg, Virginia, and of the Natural Well, Duplin County, 

 North Carolina ; Pliocene ( ?) of the north end of the Dismal Swamp, Virginia ; 

 Burns and Shaler. 



Shell smooth or slightly concentrically undulate, and with faint incremental 

 lines ; ovate, nearly equilateral, the beaks moderately elevated ; hinge delicate, 

 hinge-plate narrow, excavated ; pallial sinus deep but only moderately high ; 

 base arcuate, ends rounded. Lon. 14, alt. 11.5, diam, 7.50 mm. 



This species bears a very marked resemblance to C. subdiaphana Cpt., 

 and differs, from it chiefly in being more equilateral and with more nearly 

 equally rounded ends, and in having the area occupied by the pallial sinus 

 proportionately less high. 



The following genus is anatomically unknown, but its hinge is remarkably 

 like that of Cooperella, and the habit of the shell is much the same in spite of 

 the almost 1 unsinuate pallial line. 



Genus CYAMTUM Philippi. 



Cyainium Phil., Arch. f. Naturg., i., p. 50, 1845. Type C. antarcticum Phil., loc. cit.; not 

 Cyamea Kroyer, Crustacea, 1843, nor Cyamium H. and A. Adams, 1857 (ii., p. 476), 

 nor Jeffreys, Brit. Conch., ii., p. 237, 1863. 



Shell small, thin, smooth, ovate, with an obsolete amphidetic ligament ex- 

 ternally, and a short, strong, oblique internal resilium ; hinge-plate narrow 

 with, in the right valve, two subumbonal divaricating bifid cardinals, and, in 

 the left valve, three more slender, not obviously bifid, cardinals ; laterals, 

 none in either valve ; pallial line narrow except near the posterior muscular 

 impression, where it is irregularly wider or slightly insinuated ; adductor scars 

 narrow, elongate ; margin of the valves entire. 



This shell is perfectly distinct from the Turtonia of the northern hemi- 

 sphere, with which it has been most unaccountably confounded. The type 

 of dentition and aspect of the shell are entirely different. The characters of 

 the hinge recall Cooperella, which has, however, a deep pallial sinus. The 

 exact place of this genus can only be settled when the anatomical characters 

 are known, but the appearance of the pallial line in the adult leads me to sus- 



