Trof. 0. C. Marsh — Gigantic Ceratopmlce. 



247 



determined with certainty, but various spines, bosses, and plates 

 have been found, that clearly pertain to the dermal covering of 

 Triceratops, or nearly allied genera. Several of these ossifications 

 were probably placed on the back, behind the crest of the skull 

 (Woodcut, Figs. 33-34), and some of the smaller ones may have 

 defended the throat, as in Stegosaurus. 



29 



33 



34 



Fig. 26. — Dermal plate of Triceratops ; top view ; one-eighth natural size. 

 Fig. 27.— Bottom view of same. Figs. 28 and 29. — Side and end views of same. 

 Figs. 30-32. — Dermal plate of Triceratops; top, bottom and side views; one- 

 eighth natural size. 



Fig. 33. — Dermal ossification of Triceratops ; side view; one-half natural size. 

 Fig. 34. — Front view of same. 



The remarkable extinct reptiles here briefly described present 

 many characters which separate them widely from all other known 

 Dinosaurs. Some of these characters ai^e evidently the result of a 

 high degree of specialization, but there are others that cannot be 

 thus explained. The specialization evidently began in the skull, 

 and there reached its greatest development. The peculiar armature 

 of the skull has a partial parallel in the genus Phnjnosoma among 

 the recent Lizards, and Meiolcmia among the extinct Turtles. A 

 suggestion of the parietal crest may be seen in the existing Chameleo, 



