368 PROCEEDINGS OF THE SCIENTIFIC ASSOCIATION. 



Area centrota Guppy. 



Proceedings of the Scientific Association, p. 175 (Dec. 1867). 



This species was described as a fossil, but I have since as- 

 certained that it is likewise living on our coasts, having been 

 collected by myself on the shores of the Gulf of Paria, and 

 by Mr. Carr on the South Coast. Its umbones are often, 

 pink or red, which color is visible inside as well as outside 

 and the shell has a hairy epidermis, generally worn off at the 

 umbones. Height 17, length 24 mill, The following is the 

 original description : 



" Transversely subrhomboidal, with a strong wide carina- 

 tion running from the umbo to the posterior angle ; ornament- 

 ed with many (36-38) squamosely nodose radiating ribs each 

 with a fine subsidiary thread-like rib in the nrrrow interstice ; 

 anterior margin short, rounded ; posterior margin strongly 

 sinuate, angulate above with the hinge-line and forming a 

 more rounded angle with the strongly crenate lower margin. 

 Hinge-teeth small in the middle of the straight hinge, but 

 becoming larger and diverging considerably towards the 

 angles ; ligamental area more or less grooved, especially an- 

 teriorly." 



Th racia diss im L lis. 



Ovatc-oblong, compressed, white, roughened by numerous 

 line granules which are generally arranged in lines radiating 

 In >m the umbo; trar ely excentrically plaited ; anteriorly 

 rounded, posteriorly vertically truncate, with a keel (most 

 prominent on the smaller valve) running from the umbo to 

 the lower posterior angle. Height 27, length 40, thickm 

 15 mill. 



This is nearly allied io T. plicaia, which Peeve (C. I. 

 Thracia, 7) con ditto bo. Our shell is rather interme- 



