EXTINCT BATBACHIA. 391 



The bone also expands distally, and is divided by a groove. The oppo- 

 site halves of the respective ends are not continuous, and the bone is 

 not much contracted medially, but probably broken. I do not think 

 that the ulna and radius cross each other continuously (as represented 

 in Prof. Wyman's figure at the page above quoted), although this is the 

 only explanation of their position in the fossil, in case there are two 

 elements. The other alternative is that they are confluent, in my opin- 

 ion the more probable hypothesis. 



The left hand exhibits four digits, of which the third from the inner 

 is the longest. The number of the phalanges is 2, 3, 4 ? ; the last of the 

 third digit inferential ; the fourth digit is imperfect. The carpus is not 

 osseous. The ungueal phalanx of the first digit is narrow, of the second 

 enlarged at the end (perhaps a side view). The femur is longer than 

 the humerus, and slightly curved, the shaft presenting an angle along 

 its inferior aspect, the distal end a little expanded and truncate. The 

 lower leg is represented by but one bone, which is elongate, with sub- 

 cylindric shaft and expanded truncate proximal end. There is no hind 

 foot preserved. 



Length of cranium (median), 0.025 m. ; do. do. oblique from angular 

 bone, .033 ; greatest width of cranium, .033 ; length of five anterior ver- 

 tebrae, .012; [do. of humerus, .018; do. of fore-arm, .0113; do. of digit 

 No. 1, .0120; do. of digit No. 2, .0145; do. of digit No. 3, .0195; do. of 

 vertebral column preserved, .045 ; do. of femur, .023 ; width of vertebral 

 centrum, .0025 ; do. of end of humerus, .0065 ; do. of end of femur, .0077. 



The specimen described is the typical and only one known. Besides 

 generic characters, the present species dififers from the AmpMbamus gran- 

 diceps, Cope, in the relatively larger limbs, and especially relatively 

 longer hind limbs. 



TuDiTANUS, Cope. 



Proceedings American Philosophical Society, 1871, 177. 



Cranium broad, flat, orbits anterior, bones more or less sculptured. 

 Teeth on premaxillary and maxillary bones of nearly equal sizes. Three 

 pectoral shields sculptured externally. Form lizard-like ; two pairs of 

 limbs of medium proportions. 



This genus is established on two species, of which the collection con- 

 tains nearly entire specimens. In these no chevron abdominal rods or 

 scales can be discovered, and it is not probable that they exist. The pres- 

 ence of the pectoral shield distinguishes this genus from Dendrerpeton, 



