FOSSIL FOOTPRINTS OF THE JURA-TRIAS. 545 



there was a long metatarsus, or heel, on which the creature rested. The tail sometimes 

 dragged just before the owner came to rest but at other times was held clear of the 

 ground as a counterpoise to the anterior part of the body as in other genera. Anomoe- 

 pus represents a group of small, lightly built creatures ranging in size from .1. minimus, 

 about three feet in length, to A. crassus, a New Jersey form, six feet long. They are 

 among the most numerous and interesting of all of the ichnite genera with the exception 

 of Anchisauripus. 



The genus Fulicopus, which the writer has separated from the preceding group, 

 shows a greater amount of weight borne on the hind limbs while sitting, the manus rest- 

 ing but lightly as with the kangaroo. The feet resemble those of Anchisauripus more 

 than those of Anomoepus, there being less divarication or diverging of the digits, though 

 the position of the hallux is as in the latter genus. A curious heart shaped impression 

 frequently occurs just behind and between the impressions of the heels and tliis was 

 attributed by Hitchcock to the end of a truncated tail, but the writer believes it to have 

 l)een made by a callosity beneath the apposed extremities of the ischial bones. Hypsilo- 

 phodon, of the Wealdeu of Europe, most nearly suggests the probable skeletal characters 

 of the Anomoepodoid forms and as Professor Osborn has shown, presents the most primi- 

 tive characters of any known Orthopod. It is difficult to conjecture the probable habits 

 of Anomoepus, other than that the animals were herbivorous. They pi-obably came to 

 the mud flats mainly for breeding purposes as their tracks very frequently exhibit a dis- 

 tinct sexual dimorphism between the footprints of the two individuals. 



A very striking though rare form, Otozoum, has been placed by the present writer 

 among the Orthopoda although the structure of its foot is unlike that of any known dino- 

 saur. Otozoum is probably bipedal though there is a possibility that the great pes may 

 have obliterated the track of the much smaller manus. The foot is plantigrade, tetra- 

 dactyl, with all of the digits pointing forward and with rounded pellet-like claws and a 

 broadly expanding web or fleshy pad extending some distance beyond the ends of the 

 digits. Its probable function was that of supporting the creature on soft mud rather than 

 a natatorial one. The phalangeal formula of the pes is typically dinosaurian, while that 

 of the manus, 2. 3. 3. 3. 3, is amphibian or cotylosaurian and would be absolutely unique 

 in a dinosaur. The manus is rarely seen and is so obscure that there is a reasonable 

 doubt as to the correctness of its interpretation. In one instance a dragging tail is shown 

 which is absent in all other specimens and which is evidence in favor of the belief that 

 the animal is a biped. Otozoum has the largest track of all, measuring twenty inches in 

 length, but the author has no conception of the appearance of the creature itself. 



Among the so called leptodactylous or narrow toed tracks, are many made by bipedal 

 forms which were doubtless dinosaurs, some carnivorous, and some, judging from the 



