i44 POPULAR SCIENCE MONTHLY. 



tion to their duty of supporting their owner's weight, had to assume 

 the grasping function as the hand relinquished it, and the claws became 

 in consequence great talons, differing thus markedly from those of the 

 earlier types. 



One seems, therefore, justified in interpreting a second group of 

 tracks, much larger than those of the Middletown slab, sharp clawed 

 and with a very narrow sinuous tail trace, as having been made by a 

 dinosaur of this group. If one should picture an animal about twenty 

 feet in length, weighty in build, with talon-like hind claws, and there- 

 fore with small fore limbs and with a fairly erect posture so that the 

 tip of the rather short heavy tail touched the ground, one would have 

 a fair notion of this the maximum form, both in size and in degree 

 of specialization of the Connecticut valley carnivores. 



The other group of carnivorous dinosaurs were of a very different 

 sort, always retaining their agility and the grasping power of their 

 fore limbs, but not increasing very materially in bulk. A beautiful 

 example of this race from the Jurassic beds of Wyoming has recently 

 been mounted at the American Museum of Natural History, New 

 York, and has been given the name of Omitholestes, the bird robber, 

 in allusion to its supposed habits. It is a slender animal with an ex- 

 tremely long tail. The hind limbs are fitted for locomotion par excel- 

 lence, while the fore limbs are more slender with but three very long 

 fingers in the hand, admirable for grasping elusive prey. 



In studying the footprint slabs one frequently comes across some 

 very small impressions, hardly exceeding three inches in length, 

 three-toed, with no indication of a grasping claw behind, nor of a tail 

 trace. One might be apt to attribute these little footprints to the 

 young of the larger species until one notices the great interval between 

 the successive tracks, a distance six to eight times the length of the 

 foot itself. This of course gives evidence of extremely long limbs, so 

 that the name of Grallator, he who walks upon stilts, which has been 

 given to this group, is not inapt. While no skeletons are known from 

 the same horizon with which the footprint may be compared, it seems 

 safe to consider it one of these aberrant carnivores, of very slender 

 build, agile, and of habits possibly similar to those of the wading birds. 



It is but just to the earlier naturalists to say that we have no abso- 

 lute proof that Grallator was not a true bird, but that it was seems 

 doubtful, as the foot agrees in structure with that of known dinosaurs, 

 and birds are totally unknown from so remote a period. 



Herbivorous Dinosaurs. 

 Plant feeding dinosaurs are known by their skeletal remains only 

 from the Jurassic and Cretaceous periods, but that they existed during 

 the earlier Triassic seems indubitably certain from the fact that their 



