NO. 2127. OSTEOLOGY OF THESCELOSAVRUS—OILMORE. 615 



At the present time the fossil remains of Thescelosaurus are known 

 only from the Lance formation in three widely separated localities, as 

 shown in the accompanying map, see figure 20. These are the Nio- 

 brara County area in Wyoming, Deer Ears Buttes in South Dakota^ 

 and the Hell Creek area in Montana. 



RESTORATIONS OF THESCELOSAURUS. 



The skeleton restoration here given, plate 80, is based upon the 

 type-specimen of Thescelosaurus neglectus. The reptile is represented 

 about one-twelfth natural size. The pose was determined after a 

 careful study of the type-specimen and other aUied forms, and it is 

 therefore believed to be an attitude often assumed by the animal 

 during hfe. When ahve this animal was about 10 feet in length and 

 4 feet high in the position here represented. The shade4 portions 

 show bones that are present in the type or other supplementary 

 specimens. The missing parts are restored in outhne, the neck and 

 skull being drawn after HypsilopTiodon foxii, its nearest relative, with 

 sUght modifications of the cervical ribs. See plate 82. 



The complete presacral region is indicated as consisting of 25 

 vertebrae, 16 being regarded as dorsal and 9 as cervical. This number 

 is probably not far from the correct vertebral formula, and is the same 

 as found in two species of Camptosaurus. It at least gives the skeleton 

 the form of a compact, well-balanced animal. In hfe this reptile was 

 evidently strong and agile in movement. The tail was long, equahng 

 one-half the entire length of the skeleton and doubtless served as a 

 balancing organ when the upright bipedal posture was assumed. The 

 dorsal, sacral, and caudal regions throughout their entire length were 

 strengthened by a series of ossified tendons. 



In plate 81 is shown a hfe restoration modeled by the author and 

 based upon the type-skeleton, and it will perhaps give a more graphic 

 idea of the life appearance of the animal than could be obtained from 

 the articulated skeleton. In preparing the restoration an attempt 

 was made to express the light, agile nature of TJiescelosaurus as is 

 so clearly indicated by the skeleton and especially by the cusorial 

 structure of the hind limbs. 



EXPLANATION OF PLATES. 

 Plate 79. 



View of the upper or right side of the skeleton of Thescelosaurus neglectus Gihnore. 

 Type, Cat. No. 7757, U.S.N.M., about one-twelfth natural size. Shows the bones of 

 the skeleton in nearly the position they occupied when found and as now exhibited. 



The nonshaded portions represent restored parts. Page 611. 



Plate 80. 



Restoration of the skeleton of Thescelosaurus neglectus Gilmore. About one-twelfth 

 natural size. Based upon the type-specimen, with head and neck restored from 



