432 THE POPULAR SCIENCE MONTHLY. 



joints of the toes, like the tracks of the ostrich, turkey, and our com- 

 mon domestic fowls. The feet are invariably trifid, and the number 

 of phalanges corresponds perfectly to that observed in the toes of all 

 living birds, viz., three in the inner, four in the middle, and five in the 

 outer toe, including the claws. The inner phalanges are united to the 

 lower leg-bone abreast of each other, a little back of the middle one, 

 and thus the imprint may also show rounded impressions made by the 

 heel, which have been mistaken for phalangeal markings. This thick- 

 toed group invariably took very long steps, corresponding well with 

 the ordinary gait of their living representatives. One of them, with a 

 foot less than three inches long, had a stride of 25 inches, showing 

 a general structure like that of the waders. Moreover, the entire 

 width of the track-way is scarcely greater than that of each individual 

 foot, indicating a very narrow body, stilted high upon long legs. The 

 smallest of this group may be compared with the living snipe ; the 

 largest, having a foot 18 inches long, must have equalled in size the 

 largest of the recently-extinct birds of New Zealand, the Deinomis 

 giganteus, 10 feet high. The principal genus is the Brontozoum (the 

 animal giant) ; and of the thousands of examples of those yet ex- 

 humed, not one shows any features in addition to those described, 

 neither a fourth toe, the trace of a front-foot, nor any indication of a 

 tail. Hence, though suggestions as to their reptilian character are 

 abundant, we shall wait for proof that some distinct reptilian feature 

 is joined to the ornithic, before allowing that the Brontozoum, or 

 Grallator, were not true birds. 



But the next group gives evidences, neither scanty nor ambiguous, 

 to prove the existence of a large number of " ornithic reptiles," or " rep- 

 tilian birds." This order is now entirely extinct, and was first made 

 known to the world by E. Hitchcock's description of the " ornithoid 

 lizards, or batrachians." He saw that some of the characters w T ere 

 ornithic, and that others were reptilian, so that he was compelled, 

 though reluctantly, to refer them to an altogether new group of life. 

 Since this reference, an abundance of discoveries has confirmed these 

 views ; and the name of Herpetoids has been suggested for them by 

 Prof. Dana. 



The general form of the animal was kangaroo-like, with enormous 

 hind-limbs, a prominent tail, and small front extremities, which were 

 rarely if ever brought to the ground so as to make an impression. The 

 animal may often have walked only upon the trifid hind-feet, showing 

 neither the front-feet, the long shin-bones, nor the caudal appendage. 

 We have seen such rows of trifid impressions, 25 or 30 in number, 

 which might hastily be referred to the feet of birds. But, though the 

 general appearance is ornithic, and the number of phalanges agrees 

 with those of birds, the thirty-first impression reveals a kangaroo-form 

 on all-fours two small five-toed feet in front, two trifid impressions 

 of larger dimensions at the end of a long heel-mark behind, followed 



