DESCRIPTION OF A NEW TURTLE FROM THE SACRAMENTO 

 RIVER, BELONGING TO THE FAMILY OF TRIONYCHIDiE. 



BY J. J. KIYERS. 

 University of California. 



Aspidonectes Californiana. 



A robust species, longer than wide, tlie general form being 

 sub-ovate, the front edge of the carapace forming an arc to 

 the shoulders, then gradually widening to behind the mid- 

 dle and then decreasing to the caudal region, where the 

 broad flap is somewliat acuminate. The length of the cara- 

 pace, including the flap or margin, is 10 inches; at the ends 

 of the arc across the shoulders, 7 J inches; at the widest 

 part behind the middle, 8 J inches. The color above is dark 

 plumbeous, mottled v/ith light gray, but there are large 

 patches of cloudy black dispersed over the upper surface. 

 The central area of the carapace covering the osseous por- 

 tion has a smooth epidermis, but the margins and flats are 

 rugose tuberculate. The edge of the front margin of the 

 shield has a distinct row of large tubercles; there are also 

 some much flattened tubercles, that are connected with them 

 somewhat irregularly alternate; there are also a series of 

 compressed tubercles just behind these, and situated upon 

 the upper edge of the front margin, which continue all 

 round the flaps; but on the outer edge of the bony portion 

 of the carapace this single series of tubercles runs into a 

 greatly developed and numerous series of rows of tubercles, 

 situated upon the ventral flap and reaching upon the cara- 

 pace proper; the central row isVell defined, numbering ten 

 tubercles, and forming what maybe called the hind portion 

 of a dorsal ridge. At the front end of the dorsal ridge, or 

 keel, and continuous with the front margin, is a prominent 

 tumor or oil gland; it is sub-circular, of an inch and a quar- 

 ter in diameter; it is easily probed to the depth of five- 



2d Seb., Vol. n. December 20, 1889. 



