R. S. Loll — Dinosaurian Distribution. 19 



with Ankylosaurus of the Laramie. All three, according to 

 Williston, were derived from Polacanthus of the Wealden of 

 Europe. 



The Gosau beds of Wiener Neustedt near Yienna, probably 

 equivalent to our Judith River, contain a number of armored 

 forms such as Struthiosaurus (Nopcsa 1902) and Acanthopho- 

 lis (Nopcsa 1902) some of which, at least, probably pertain to 

 the same race. 



Ceratopsia. 



The Ceratopsia have a relatively brief career, — Stenopelix, 

 the pelvis of which resembles that of Triceratops, being the 

 earliest possible representative among known forms. It is 

 found in the Neocomian of Germany. The remains described 

 by Seeley (1881, pi. xxviii, fig. 4) from the Gosau formation 

 under the name of Cratceomus ( = Struthiosaurxis / Nopcsa 

 1902) contain what appears to be a ceratopsian left supra- 

 orbital horn-core which would seem to represent a stage of 

 evolution equivalent to Ceratops of the American Judith 

 River. Nopcsa (1902, p. 7) is of the opinion, however, that 

 the horn -like bone in question represents a dorsal spine after 

 the manner of those of Polacanthus. This, together with 

 the total absence of two-rooted teeth of the ceratopsian sort 

 among the number preserved at Yienna, casts grave doubt upon 

 the existence in Europe of this remarkable group. 



The American Judith River ( == Belly River of Canada) 

 contains two stages in the evolution of the Ceratopsia, Mono- 

 clonius and Ceratops, as well as the somewhat aberrant 

 Centrosaurus described by Lambe (1904). The Laramie 

 deposits which follow later after a hiatus of some 2,000 or 

 more feet of marine strata contain the terminal members of 

 this race, Triceratops and Torosaurus. The geological distri- 

 bution and phylogenies are shown in figure 1. 



V. Geographical Distribution. 

 Theropoda. 



The geographical distribution of dinosaurs presents some 

 very interesting problems, some of which, at first sight, are 

 difficult to explain. 



By far the widest spread forms are the carnivorous Theropoda 

 (fig. 2), evidently the most adaptable and of a nature not so 

 subservient to a peculiar kind of food, which was apt to be 

 local in distribution, as in the case of the plant-feeding forms. 

 These carnivores are reported in practically every locality 

 where herbivorous dinosaurs have been found, as they seem to 



