200 REPTILIA. 



of tarsals ; possibly, however, this character, known only in one specimen,, 

 is pathological. The typical and only known species is Ceratosaurus nasi- 

 cornis from the Upper Jurassic of Colorado. 



FIG. 120. 



Ceratosaurus nasicornis ; restoration of skeleton by 0. C. Marsh, one-sixtieth 

 nat. size. Jurassic; Colorado. 



It may be added that one imperfect small reptilian skeleton 

 from the Jurassic of Colorado is believed to represent a Thero- 

 podous Dinosaur with the power of leaping. It is named 

 Hallopus victor. The fore limb is relatively small with four 

 digits. In the hind limb the femur is shorter than the tibia, 

 arid there are only three functional digits with much-elongated 

 metatarsals. The astragalus is destitute of an ascending pro- 

 cess, and the calcaneum is much produced into a " heel." 



Sub-Order 2. Sauropoda. 



These are more or less massive herbivorous Dinosaurs, with 

 fore and hind limbs nearly equal in size and therefore pre- 

 sumably quadrupedal in gait. The feet are plantigrade, each 

 with five hoofed digits, while the distal series of carpal and 

 tarsal bones are apparently unossified. The brain-case is 

 completely ossified, and there is a large antorbital vacuity 

 in the skull. There is no predentary bone. The anterior 



