REPTILE RECONSTRUCTION GILMORE. 277 



plates extending from back of the skull on either side of the mid- 

 line of the back to the end of the tail, the tail being armed near the 

 tip with two pairs of bony spikes or spines. There are also a con- 

 siderable 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, protective to the extent of giving the animal a 

 most formidable appearance rather than actually useful as a defen- 

 sive instrument. 



While the fossil remains of these animals are not uncommon in 

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

 articulated bones. The one here figured is the only mounted skeleton 

 of this animal in existence at the present time. 



In plate 4, is shown a model restoration of Stegoscdvrus prepared 

 by the writer and which portrays his conception of the life appear- 

 ance of this animal. In this restoration is incorporated all of the 

 latest evidence relating to its external appearance, and is thought 

 to give a fairly accurate picture of the living animal. The recent 

 discoveries of skin impressions with the fossil remains of other 

 dinosaurian specimens makes it not unreasonable to expect that 

 Stegosaurus had a scale-like integumentary covering, instead of the 

 smooth elephant-like skin as here depicted. In the light of recent 

 discoveries we may yet hope to have still more definite knowledge 

 as to its true nature. 



That the sluggishly moving Stegosaurus had need for his bony 

 skin protection is indicated by the presence in the same geological 

 formation of large flesh-eating dinosaurs. One of the most striking 

 of these, though not the largest, is the Ceratosaurus, a carnivorous 

 animal with a large head, having jaws filled with rows of strong, 

 sharp-pointed teeth, that were well adapted to the seizing of its 

 prey and the subsequent tearing and rending of the flesh. One of 

 the distinctive features of this animal is the presence on the nose of 

 a single, well-developed horn, and it was this horn that suggested 

 to Professor Marsh the name Ceratosaurus ?iasicornis, meaning nose- 

 horned saurian or lizard. 



The exceedingly small fore limbs armed with sharp claws were 

 not at all adapted to walking purposes, so that progression must 

 have been entirely upon the strong hind legs. 



This specimen was collected near Canon City, Colorado, during 

 the years 1883 and 1884. The skeleton was found largely articu- 

 lated in the rock, but many of the bones, especially the skull, have 

 boon greatly compressed and this flattening largely determined 

 the selection of the bas-relief method of mounting it for exhibition, 

 see plate 5. The backbone stands out in bold relief from the orig- 



136650°— 20 19 



