20 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 80 



BARYPODUS TRIDACTYLUS, new species 

 Plate S 



Type. — Catalogue number 1 1,502, U. S. N. M, Consists of the posi- 

 tive and negative slabs on which is a beautifully preserved trackway. 



Type locality. — Hermit Trail, Hermit Basin. Grand Canyon Na- 

 tional Park, Arizona. 



Fig. 7. — Barypodus tridactylus.. Type. No. 11,502, U. S. N. M. 

 Diagram of trackway. Toes indicate position of the hind feet. 

 About i natural size. 



Geological occurrence. — Coconino sandstone (about 150 feet above 

 base), Permian. 



Description. — Stride about 140 mm., width of trackway about 175 

 mm. Hind foot: None of the impressions made by the pes is suffi- 

 ciently clear to provide measurements. The presence of three digits 

 is distinctly indicated by several tracks (see pi. 5). Measured across 

 the toes the foot has a width of 44 mm. Digits shorter than those of 

 manus. Length of first digit about 15.5 mm., second about 23 mm., 

 third 26 mm. It will be seen from these measurements that the toes 

 grow progressively longer toward the outside of the foot. The 



