i6 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 80 



Geological occurrence. — Coconino sandstones (about 150 feet above 

 base), Permian. 



Description. — Stride (average) about 2/"/ mm., width of trackway 

 (estimated) about 300 mm. Both of these measurements are subject 

 to revision with the discovery of better material for it is quite appar- 

 ent that the type specimen does not represent a continuous normal 

 trackway. This is indicated by the irregularity of the stride and the 

 great variation in the relative position of the tracks of the fore- and 

 hindfeet, although the manus is always placed in front of the pes. 

 The longest stride measures 320 mm., while the shortest of that same 



Fig. 5. — Nanopiis iiiaxi)iiits. Type. No. 11,506, U. S. N. M. A, 

 imprint of right forefoot; B, showing relations of fore- and hind- 

 feet of right side. About ^ natural size. 



side is only 225 mm. Hindfoot: Greatest length 65 mm., greatest 

 width 85 mm. Four toes acuminate and subequal in length. First and 

 fourth more slender than median pair, both curving inward from 

 their respective sides of the foot. Second and third having their ti]:)S 

 directed slightly outward. Sole eciual to length of toes, suboval, 

 broadly rotmded behind. That there were sharp well developed claws 

 on all four toes is shown by the long deep scratches where the foot 

 had slipped as may be seen on the left side of the trackway in plate 3, 

 Length of digit I, 34 mm., digit II, 34 mm., digit III, 34 mm., digit 

 IV, 36 mm. Forefoot: Length (estimated) about 43 mm., width 

 about 52 mm. Three toes, acuminate, clawed, and probably subequal 

 in length. The sole in most of the imprints is obscure but in the best 



