2 BULLETIN 110, UNITED STATES NATIONAL MUSEUM. 



These specimens were secured almos t entirely through transfer from the United 

 States Geological Survey, having been collected by field parties working under the 

 direction of the late Prof. Othniel Charles Marsh. When received at the National 

 Museum in 1898 and 1899 only a small part of the carnivore material was in con- 

 dition for study. The preparation of this material was begun in 1911 and has 

 continued, barring interruptions, up to the close of the year 1918. Practically all 

 of the known Theropod specimens in the collection have been prepared and are now 

 available for study and exhibition purposes. 



This preparatory work has been done by Messrs. N. H. Boss, G. B. Giles, 

 John M. Barrett, and Louis Goldberg, and they are to be highly commended for the 

 efficiency and skill displayed in extracting these delicate fossils from a most refrac- 

 tory matrix. 



Many of the wash drawings which are here reproduced through the com-tesy 

 of the United States Geological Survey were made by the late Mr. Frederick Berger 

 and were prepared under the direction of the late Prof. O. C. Marsh. The later 

 drawings are nearly all the work of Mr. Eudolph Weber. The photographs were 

 made by the late Mr. T. W. Smillie, and his successor, Mr. L. M. Beeson, both of the 

 United State National Museum. 



I wish to acknowledge here my indebtedness to Dr. George P. Merrill, head curator 

 of geology. United States National Museum, for the confidence expressed by his 

 unfailing support of all things pertaining to the preparation of this paper, which 

 extended over such a long period of time. I also wish to thank my colleagues, 

 Mr. J. W. Gidley and Dr. O. P. Hay, for invaluable advice on numerous occasions; 

 and especially do I appreciate the generosity of Mr. Walter Granger, of the American 

 Museum of Natural History, in supplying me with data and photographs of Antro- 

 demus specimens in advance of the appearance of his article on the same subject. 



>- THE GENUS ANTRODEMUS LEIDY. 



In 1S70 ' Prof. Joseph Leidy described the posterior half of a caudal centrum 

 to wliich he gave the name Poicilopleuron ^ valens, ami at the same time proposed the 

 generic name Antrodeinus in the event of more adequate material showing characters 

 that would distinguish it generically from the Em-opean saurian Poicilopleuron. 



Three years later, 1873, Leidy republished with a few emendations his original 



description,^ illustrated by three views of the type specimen. He recognized the 



dinosaurian nature of the animal as well as its Theropod affinities. The text of 



this paper was under the caption PoicilopleuTon valens, but in the explanation of 



1^' the plate illustrations they were correctly designated as Antrodemus. 



In 1890^ Zittel referred the genus to the family Megalosauridae. 



In 1901 ^ Hay referred to this genus all of the described species of the genus 

 Lahrosaurus, but in a later article' shows that no sufficient reason existed for dis- 

 placing Marsh's generic name in favor of Antrodemus. 



1 Proc. Acad. Nat. Sci. Phila., 1S70, p. 3, 



= In the literature it is also found spelled PoikilopleuTon and Poekilopleuron. 



' Extinct Vert. Fauna West. Terr., 1878, pp. 267-279, pi. 15, figs. 16-18. 



< HandbuchderPalaeontologic, 1890, pt. ), vol. 3, p. 722. 



<■ Bull. No. 179, U.S. Geo!. Survey, 1901, p. 489. 



' Proc. U.S.Nat. Mus,, 190S, vol. 35, p. 353. 



