AMPHIBIAN FOOTPRINTS FROM THE MISSISSIPPIAN 357 



21 cm., but with the appearance of the prints of the forefeet the dis- 

 tance apart is 165 mm., 40 mm., 85 mm., 70 mm., 80 mm., 40 mm., 

 150 mm., and then back to 20 and 21 cm., with no more prints of the 

 forefeet. Where only the prints of the hindfeet appear the impres- 

 sions are deeper. 



The hindfeet were 60 

 mm. in length, and 20 to 

 25 mm. in breadth. They 

 had five digits, the middle 

 digit being the longest and 

 the two inside of it being 

 only slightly shorter and 

 lying close together. Their 

 outer ends were slender and 

 flexible and usually curved 

 inward toward the middle 

 toe. The two outer digits 

 formed wide angles with the 

 middle one and were shorter 

 than the inner ones. The 

 second toe was webbed to 

 within 8 mm. of the tip, the 

 third toe to within 23 mm. 

 of the tip. The impression 

 of the web is well preserved 

 in only one impression of 

 the hindfoot. The heel was 

 narrow, 10 to 12 mm. in 

 length, and not well enough 

 distinguished in the prints 

 to determine its exact shape. 



The forefeet were 45 mm. in length and had four digits. The 

 three inner digits were subequal in length, the two inner being more 

 flexible and incurved near the ends. The outer digit is two-thirds as 

 long as the second. The webbing extends about half the length of 

 the digits. The heel impression is broader than that of the hindfoot. 



The distance between the inner parts of the impressions of the right 



Fig. I. — Dromopus aduncus i natural size. 



