NATURAL SCIENCES OF PHILADELPHIA. 25 



the last joining the last costal by a very short suture. The mar- 

 gin of the carapace is regular without notch behind or elsewhere. 

 The plastron is small, rather broad, and rounded in front, and 

 much contracted and acute behind. The bridge is rather wider 

 than in C. angustatus, and more as in Chelydra. The anterior 

 lobe is immovable in the dried specimen. Pectoro-abdominal 

 suture transverse, length -of pectoral on median suture equal 

 abdominal and two-thirds femoral length, and equal to that of 

 the anal. Latter much longer than wide. The abdominal plate 

 is the only one which covers the bridge from within, but does not 

 extend quite half-way across. Each is met by two large ingui- 

 nals, which are broadly in contact with each other, and are 

 broader than long. 



The color of the carapace is brown, but wherever rubbed of a 

 wax-yellow. The marginals at the bridge are principally a 

 strong yellow, which color covers the whole of the plastron. 



The soft parts are preserved in alcohol. The head is large for 

 the size of the carapace, and is remarkably broad, and with rather 

 short muzzle. This projects, however, much beyond the mouth, 

 the end of the under jaw visible when closed, being scarcely 

 beyond the margin of the orbit. Beak short, obtuse, not dentate ; 

 an obtuse festoon of the tomia below the orbit. Two beards. 

 Head covered with skin above, except from the line of the poste- 

 rior margin of the orbits to the end of the muzzle, which is pro- 

 tected by an undivided horny plate. 



The skin is but slightly granular. There are five curved scuta 

 on the ipner side of each fore foot, and a single row of scuta 

 above on each digit. The fore feet are webbed to the bases of the 

 ungues. The hind feet are well palmate, and with a free outer 

 web supported by a clawless toe. There are six curved scuta 

 on the inferior outer face of the base of the lower leg, of which 

 the first and third reach the external margin, and the others are 

 more internal except the lowest, which is very small. The tail is 

 very short, depressed, and incurved, with a terminal compressed 

 corneous scale. It is smooth, or without tubercles, above and 

 below, but anterior to the anus above are three pairs of very 

 small tubercles, one on each side of the median line. 



Color of soft parts dirty white below, dark brown above; sides 

 of head with close j^ellow reticulations behind. Throat and 

 lower jaw yellow; a dark spot on each side of the symphysis con- 

 1872.] 3 



