THE FOSSIL FOOTMARKS OF THE UNITED STATES. 217 



Gems XIII. PALAMOPUS. 



Bipedal ; tetradactjlous ; toes all directed forward, spreading 

 moderately ; leptodactjlous ; essentially plantigrade. 



Species 1. Palamopus Dananus. (PI. XI. Figs. 1, 2.) 

 No. 149 in Cabinet. 



Angle between the inner and second toes, 25° ; between the sec- 

 ond and third, 30° ; between the third and fourth, 13° ; between 

 the inner and outer, 67°. Length of the inner toe, 2 inches ; of 

 the second, 2.5 inches ; of the third, 4.7 inches ; of the outer, 2.3 

 inches ; of the third or longest toe beyond the others, 2.7 inches. 

 Distance between the tips of the first and second toes, 2.4 inches ; 

 between the second and third, 3.4 inches ; between the third and 

 fourth, 3 inches ; between the outer ones, 4.7 inches. Length of 

 the heel, 3.7 inches ; breadth behind, 2 inches ; wider before. 

 Probably web-footed. Length of the foot, 8.5 inches ; of the step, 

 21 inches. Axis of the foot and line of direction coincident. 



Remarks — The above dimensions were measured from Plate 11, 

 fig. 1. Fig. 2, which is the next track on the only slab of this spe- 

 cies yet discovered, appears to have been somewhat distorted by a 

 subsequent track of Brontozoum giganteum on the same stone. 

 It is possible, however, that this was not the cause of the differ- 

 ence between them. 



This track was discovered by Mr. William S. Clarke, of the 

 Senior Class in Amherst College, on the railroad, in the south- 

 east part of Northampton. It is dedicated to S. L. Dana, M. D., 

 LL. D., of Lowell. 



Affinities of the Genus. — The resemblance between the tracks 

 of this genus and the feet of some living batrachians is rather 

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