1895.] NATURAL, SCIENCES OF PHILADELPHIA. 385 



their lateral apices each forming the apex of an ohtuse angle 

 whose anterior side is formed by the transverse anterior face 

 of the postgular and the oblique lateral face of the pectoral plate. 

 Pectoral plates rhomboidal, their median suture longer than the 

 anterior (pecto-gular) suture and their posterior (pecto- abdominal) 

 suture equalling the length of the lateral margin of the plate. 

 Abdominal plates rhomboidal, transversely elongate, their lateral 

 margins slightly convex, posterior margins truncate. Upper man- 

 dible emarginate with a well defined hook. A triangular emargi- 

 nate rostral shield reaches median line of orbits. A pair of barbels 

 at symphysis of lower jaw; the cervical folds and tubercles nearly 

 obsolete. Crown and rostrum olive; black-spotted; rest of dermal 

 surface bluish- white; the upper head and neck streaked and spotted 

 with irregular black lines. Two black bands pass back from the 

 eye across and above tympanum and join on foreneck, reachiug 

 thence to forearm; continuous black stripes above and below this 

 reach from the temples and base of mandibles to base of neck. Su- 

 perior surface of legs and feet and tail irregularly marbled with 

 black. Plastron, mandibles and claws olive yellow. Plates of 

 carapace olive, with black margins. The skull, viewed laterally, 

 shows a depressed interorbital, convex frontal and depressed occipital 

 profile. 



Measurements: Length of plastron (median) 41 mm.; greatest 

 width of bridge (interaxillar width), 35.5; width of carapace 

 between anterior margins of seventh pair of marginal plates, 53. 

 Greatest length of skull, 23; greatest width of skull, 14.5. 



The specimen above described was found dead in the Emory 

 river, and had evidently just been thrown there by one of the nu- 

 merous urchins who were fishing near the place. The anterior half of 

 the carapace was missing. The animal was apparently two-thirds 

 grown. 



A comparison with several alcoholic specimens of A. odoratui of 

 the same age, taken near Philadelphia by Dr. Jos. Leidy, shows so 

 many decided peculiarities in the Tennessee example that I have been 

 almost induced to give it a new name. 



The most prominent of these is the truncated shape of the plas- 

 tron and the rhombic outlines of the abdominal and pectoral plates, 

 the former wholly lacking the deeply cleft emargination of the axil- 

 lary border. The shape of the skull is quite different, and the 



