384 PROCEEDINGS OF THE NATIONAL MUSEUM. tol. 5-L 



der and conjecture as to the real character of their feeding habits. 

 They would at least appear to indicate that their food consisted of 

 the most succulent of terrestrial plants. The structure of the large, 

 broad feet suggests they were land-haunting, doubtless of low, 

 swampy regions rather than the upland, and such an environment 

 would be the more natural place to find the soft plant life necessai*y 

 for their sustenance. In addition to the small head, the great dif- 

 ference in the proportions of the fore and hind legs, the one most 

 striking external feature of /Stegosaurus, is the unusual development 

 of the skin armor, consisting as it does of two parallel rows of erect 

 alternating bony plates that extend from back of the skull on either 

 side of the midline of the back nearly to the end of the tail ; the tail 

 being armed near the tip with two pairs of large bony spikes or 

 spines. There is also a considerable number of small rounded bony 

 ossicles that in life were held in the skin and probably formed a 

 mail-like protection to the head and neck. The primary purpose of 

 this armor must have been for defense, probably protective to the 

 extent of giving the animal a most formidable appearance rather 

 than actually useful as an offensive instrument. 



While the fossil remains of these animals are not uncommon in 

 our museums, they consist for the most part of the scattered and dis- 

 articulated bones of the skeleton. Only rarely have fairly complete 

 skeletons been found and hitherto there has existed in our museums 

 but one mounted skeleton, that of the Yale University Museum in 

 New Haven, Connecticut, although now dismantled due to the tear- 

 ing down of the old museum building preparatory to the erection of 

 a new and more spacious institution. 



THE MOUNTED SKELETON OF STEGOSAURUS STENOPS. 



Thus the recent addition to the exhibition collection of the section 

 of Vertebrate Paleontology in the United States National Museum of 

 a mounted skeleton of Stegosaurus stenops makes it the only skeleton 

 of /Stegosaurus now on exhibition. Photographs as it appears in the 

 exhibition hall are rej)roduced in plates 57-61. 



The present specimen is a composite skeleton — that is, made up 

 of the bones of more than one individual — but by following the type 

 of the species (No. 4934, U.S.N.M.) the most perfect single skeleton 

 known, as a guide, it is believed the mounted specimen gives a very 

 accurate conception of the skeletal structure of this animal. It is 

 based primarily on a specimen (No. 6531, U.S.N.M.) consisting of 

 the nearly complete articulated tail, sacrum, the greater number of 

 the dorsal vertebrae, pelvis, numerous ribs, and dermal plates. The 

 other bones introduced are from individuals found in the same de- 

 posit of fossils, known to the collectors as " Quarry 13," located 

 about 8 miles east of the famous Como Bluff in Albany County, 



