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PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 4ft. 



miprepared specimens in the collections of a nearly complete scapula 

 and coracoid (No. 7760, fig. 10) now enables me to give a full descrip- 

 tion of these elements. This specimen was collected by Mr. J. B. 

 Hatcher in 1891, at Deer Ears Buttes, Butte County, South Dakota 

 (see 2, fig. 20), and its occurrence there greatly extends the known 

 geographical range of the genus. 



Relatively the scapula of Thescelosaurus is short, and the back- 

 ward extension of the blade is somewhat more pronounced than in 

 either Hypsiloyhodon or Camptosaurus. The upper half of the blade 

 is thin, with flattened inner and outer surfaces. The truncated and 

 unfinished appearance of the upper margin suggests the presence of 

 a cartilaginous extension of the blade upon the sides of the thorax, 

 such as is present in the extinct Mosasaurs and in recent lizards. 



Fig. 10.— Left scapula and coracoid of Thescelosattrus neglectus Gilmoee. No. 7760, 

 U.S.N.M. J NAT. SIZE. Lateral vtew. c, Coracoid; g, glenoid cavity; s, suture between 



SCAPtJLA AND CORACOID; SC, SCAPULA. 



The articulating end is expanded both vertically and transversely 

 and presents two distmct faces or facets on the lower end, of which 

 the longer one is for union with the coracoid, and the shorter and 

 stouter one forms one-half of the glenoid fossa (fig. 10). On the ante- 

 rior margin above the articulation for the coracoid is a short but 

 prominent ridge that subsides rapidly upon reaching the flattened 

 surface of the shaft. Viewed from the front the articulated scapula 

 and coracoid is bowed from end to end and would thus conform 

 closely to the outward curve of the body cavity. Only upper por- 

 tions of the blades of the scapulae are preserved with the type- 

 specimen, but these agree exactly with the bone here described. 

 Compare figures 9 and 10, also plate 79. 



