218 AN ATTEMPT TO DESCRIBE THE ANIMALS THAT MADE 



Striking. Some of the Ranidae have only four toes on their fore 

 feet. Now, as we have evidence of the probable existence, during 

 the triassic period, of the biped batrachian Otozoum, we may, with 

 no little probability, refer the Palamopus to the same tribe, until 

 proof shall be obtained of its quadrupedal character. The P. 

 Dananus is the only fossil animal in New England whose tracks 

 decidedly indicate webbed feet. 



Group VI. aUADRUPEDAL BATRACHIANS. 



Quadrupeds, with 4 to 5 blunt pachydactylous toes, and webbed 

 feet, especially the fore feet. Heels broad and irregular. Impres- 

 sion of the toes on the mud uniform through their entire length 

 (i. e. not showing phalangeal enlargements). Rudiment of a sixth 

 toe on the hind foot, and of a fifth toe on the fore feet (?) . 



Genus XIV. THENAROPUS, King. 



Figured and described by Dr. King, in American Journal of Sci- 

 ence, Vol. XLVIII. p. 348. 



Description the same as that of the Group. 



Species 1. Thenaropus heterodactylus, King. 

 (PI. XVI. Figs. 1, 2.) 



No. 191 in Cabinet. 



Fore foot. — Toes four, with the rudiment of a fifth (?) on the 

 inside, shown on the track by a protuberance. Divarication of 

 the lateral toes, 90° ; of the inner and second toes, 20° ; of the 

 second and third, 30° ; of the third and fourth, 40°. Length of 

 the inner toe beyond the web, 1.2 inch; of the second toe, 1.4 

 inch; of the third, 1.5 inch; of the fourth, 1.1 inch; of the foot, 



