54 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8o 



tively short with rounded extremities, without claws ; sole of pes 

 elongated, narrowed behind. Forefoot turning strongly inward and 

 placed in front of hindfoot. 



Genotype. — Paraharopus coloradcusis (Lull) 



PARABAROPUS COLORADENSIS (Lull) 



Plate 15, fig. 7 

 Megapezia ? coloradcnsis Lull, R. S., Amer. Journ. Sci., Vol. 45, 1918, p. 341. 



In establishing this species. Lull had as type materials " three small 

 slabs of red impure sandstone, one apparently of the manus obscured 

 by crushing" and mud-cracking, another of the pes, and a third with 

 two impressions each of hand and foot, which determine the width 

 of trackway but not the length of stride.'' From a study of these 

 composite materials he depicted the plan of the feet as shown in 

 figure 26. 



A series of tracks (No. 11,598, U. S. N. M.) of the left side from 

 the Hermit shale and from the same general locality as the type 

 specimens, shows such striking resemblances to the tracks figured by 

 Lull, except for their slightly larger size, as to at once raise the 

 question of the proper association of the imprints as illustrated by 

 Lull. This series, which is in relief, has been cast and thus afifords 

 all of the evidence of the original imprints. The manus is shown to 

 be smaller than the pes, and the digits of the former resemble those 

 of the latter in being relatively short with rounded ends without 

 claws. This fact is entirely in accord with the large number of track- 

 ways in the collection from this same region in that the toes of the 

 manus are always similar to those of the pes in the character of their 

 termination. Li other words, if one has the toes acuminate, they will 

 be pointed in the other ; if rounded in the hindfoot, they will be 

 rounded in the forefoot, etc., etc. In the large collection of trackways 

 now available from this same region, not a single exception to this 

 rule can be found. This reason alone a]:)pears to be sufhcient to show 

 that these imprints have been incorrectly associated. 



That Lull recognized this incongruity of foot structure is shown 

 by the following remarks : 



The difference in character of manus and pes is so great, except for 

 an agreement in size, that one would not, perhaps, be justified in associating 

 them together were it not for the third slab. 



Examination of the type materials made possible through the kind- 

 ness of Dr. R. S. Lull, who forwarded them to the National Museum, 

 all goes to confirm my above conclusions. The third slab, on which 



