OSTEOLOGY OP CARNIVOROUS DINOSAURS. 7 



characters indicating the Colorado saurian to be distinct from Poicilopleuron, it might be named Antro- 

 demus. 



In the original description given above the type-specimen is most accurately 

 described, and needs no further elucidation at this time. 



OSTEOLOGY OF ANTRODEMUS. 



In the pages that follow I have attempted to give, for the first time, a detailed 

 description of the complete osteology of Antrodemus (Allosaurus) valens (Leidy). 

 This work is based almost entirely upon material preserved in the paleontological 

 collections of the United States National Museum, and primarily upon specimen 

 No. 4734, U.S.N.M., known also by the collector's designation as "Sk. 7." I have 

 selected this specimen on account of the well-preserved condition of the bones and 

 from the fact that it consists of the greater part of the skeleton of a single individual. 

 Reference will occasionally be made to other individuals when important structural 

 differences are displayed, and bones not present in this skeleton will be described 

 from other specimens. 



SUMMARY OF ANTRODEMUS MATERIALS. 



The specimens in the United States National Museum now identified as Antro- 

 demus valens Leidy are as follows: 



1. No. 4734, U.S.N.M. " Sk. 7." Nearly complete skeleton from " Quarry No. 1," Canon City, Fremont 



County, Colorado. Collected by M. P. Felch, 1883-4. 



2. No. 8367, U.S.N.M. Consists of 9 cervicals, 10 dorsals, 2 sacral and 7 caudal vertebrae. Cervical 



and dorsal ribs, 6 chevron, pubes, ischia, and portions of ilium. From " Quarry C, " Albany County, 

 Wyoming. Collected by Fred Brown, 1886. 



3. No. 2323, U.S.N.M. (juvenile), consists of 8 cervical centra, 11 dorsal centra, 2 sacral centra, nu- 



merous neural processes of both cervical and dorsal vertebrae, right ilium, 2 ischia, right femur, 

 parts of many ribs, from " Quarry 9, " Como, Albany County, Wyoming. Collected by Fred Brown, 



4. No. 8423, U.S.N.M. "Sk. 5" consists of 2 maxillae, 5 dorsal centra, 5 coossined sacral vertebrae, 



3 caudal centra, parts of ilia, 2 ischia (broken), 2 pubes (broken)"; 2 femora, left hind foot, few 

 ■ bones of fore foot. "From Quarry No. 1," Canon City, Fremont County, Colorado. Collected 

 by M. P. Felch, 1884. 



5. No. 8335, U.S.N.M. Consists of right maxillary with teeth and dentary of same side, from "Quarry 



No. 1." Canon City, Fremont County, Colorado. Collected by M. P. Felch, 1884. 



6. No. 218, U.S.N.M. Type of Antrodemus valens, Leidy, consists of distal half of anterior caudal 



centrum, from Middle Park, Grand County, Colorado. Collected by Dr. F. V. Hayden, 1869. 



7. No. 8405, U.S.N.M. Consists of 5 coossified sacral centra, lateral metatarsal, phalanges of fore and 



hind feet, from "Quarry D." Como, Albany County, Wyoming. Collected by Fred Brown, 1884. 



8. No. 7336, U.S.N.M. Consists of left astragalus, from "Quarry No. 1," Canon City, Fremont County, 



Colorado. Collected by M. P. Felch, 1886. 



9. No. 8302, U.S.N.M. Consistsof ungual of digit III, fore foot from "Quarry 9," Como, Albany County, 



Wyoming. Collected by Ed. Kennedy, 1884. 



10. 8257, U.S.N.M. Consists of ungual digit II, right fore foot, from near Canon City, Fremont County, 



Colorado. Collected by M. P. Felch, 1883. 



SKULL. 



Plates 3-4. 



A complete articulated skull of Antrodemus (Allosaurus) is unknown, though 

 several more or less perfect but disarticulated skulls have been found, but none 



