274 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1918. 



years of specimens having impressions of the skin preserved shows 

 it to be made up of a series of nonimbrieating scales. 



The accompanying photographic reproduction (pi. 2, fig. 2) made 

 of a recently prepared model restoration aims to embody all of the 

 evidence of recent discoveries. Primarily it is based on the mounted 

 skeleton shown in the figure above, and was made to a scale of one- 

 fourteenth the linear dimensions of the original skeleton. 



The nonimbrieating, scale-like texture of the skin as represented in 

 the model is based with modifications on skin impressions in the col- 

 lections of the Geological Survey of Canada, at Ottawa; and al- 

 though these impressions belong to one of the more primitive Cera- 

 topsians it does not appear unreasonable to expect that all of the 

 horned dinosaurs had a scaled integument, though the pattern of the 

 scales probably varied considerably in the different genera. While 

 future discovery will undoubtedly show the incorrectness of many 

 features of this restoration, it at least graphically portra} 7 s some of 

 the discoveries made during the past decade, and which have led to a 

 much better understanding of the life appearance of these huge- 

 headed, long extinct reptiles. 



During the same geological period that the Trachodon and Tri- 

 ceratops lived there were many other and smaller kinds of dino- 

 saurs. A skeleton of one of these, now in the National Museum, is 

 shown in plate 3. This was collected in Wyoming in 1891, and it 

 was in the nature of a surprise upon cleaning the rock from the bones 

 in 1914 to find that it represented a dinosaur new to science. It was, 

 therefore, found necessary to give it a name, and the name Thes- 

 celosaurus neglectus was coined for that purpose, the last or specific 

 name being suggested by the seeming neglect on the part of those in 

 charge of this beautiful specimen which had remained in the original 

 packing boxes for 23 years after it was first discovered. 



The value of a fossil is considerably enhanced when it happens 

 to be one to which a new name is first given, for it ever after re- 

 mains the standard for comparison by which others of its kind are 

 identified. Such a specimen is called a type, and the greater the 

 number of types in a collection of fossils, usually the greater its 

 scientific importance. 



The skeleton as here shown in the reproduction occupies relatively 

 the same position as when found in the rock. The head and neck 

 are missing, as are some few parts of other bones, as shown by the 

 light-colored areas in the picture. 



The importance of preserving articulated dinosaurian specimens 

 in their original positions in the matrix can not be too highly 

 estimated, particularly where they give positive information, as 

 in the present instance, relating to the proper articulation and angu- 

 lation of the feet and limbs. Unlike the mammals, the articular 



