512 M. L. Moodie — Goal Measures Amphibian. 



ments and it is to this that our attention will be confined. The 

 opposite leg is not so complete, yet all the long bones and a 

 part of the tarsus are preserved with sufficient clearness to cor- 

 roborate the findings of the left side. 



The femur, as has been stated, is reptilian in appearance. 

 This is due to the well-rounded articular surfaces, as though 

 the endochondrium were well developed, and to the large 

 development of the greater and lesser trochanters, which are 

 quite prominent, though these are distorted and depressed 

 in fossilization. The bone is stout and well built (fig. 2) and 

 its form suggests an active habit of life. The tibia andjibula 

 are separate, and do not otherwise have sufficiently noteworthy 

 characters as to call for a special description in this place 

 except to note an unusual anterior crest on the tibia. To the 

 lower ends of these bones articulate the first row of tarsal ele- 

 ments ; the tibiale, intermedium and fibulare. The tarsus is 

 composed of nine elements arranged in three rows. 



The proximal row is composed of the tibiale, the intermedium 

 and the fibulare. On the edge of the tibiale there lies a por- 

 tion of one of the caudal vertebrae, so that the form of this tar- 

 sal element is slightly obscured. The intermedium is a small 

 rounded element lying between the larger elements. The fibu- 

 lare is rectangular and projects a considerable distance out 

 from the tibia, but articulates directly with the large lateral 

 distal tarsal. The centrale is triangular in form and is opposed 

 directly by the tibiale and tarsalia 1-3. The phalanges are 

 robust in appearance. The entire foot gives one the impression 

 of a very broad structure. The ungual phalanges were appar- 

 ently bluntly clawed. 



The unusual nature of this foot and its disturbing nature in 

 an attempted analysis of amphibian descent has already been 

 commented on,* and further discussion in this place is unnec- 

 sary. 



The tarsus of Archegosaurus described and figured by Baur|| 

 (page 509) is so incomplete and scattered that a direct com- 

 parison with the present form is not possible. Further than 

 this form I know of no species with which we may compare 

 the structures of Ichthycanthus. 



Department of Anatomy, University of Illinois, Chicago. 

 * Science, N. S., vol. xli, No. 1044, p. 34. 



