48 
simple fore and aft step. It follows that the head and fore quarters would 
be swung from side to side during locomotion. 
Feeding . There is no question that the ceratopsians were herbivor- 
ous. Tait and Brown (10) have described in detail their interpretation of 
the feeding habits, which pictures the ceratopsians shearing off the stems 
of small trees by the action of the beak. Lull (3, page 22) has expressed 
doubt as to the ability of these reptiles to rotate the head through a 90- 
degree arc, and similar objections are raised by the writer above. Lull 
considers it more likely that the heavy body was utilized to override vege- 
tation, after which the edible parts could be cropped. To this interpreta- 
tion the writer would add the possibility that the ceratopsians were also 
root grubbers, pulling up succulent roots with the hooked beak and power- 
ful jaws. In this operation the hind legs would play an important part, 
owing to the great power that they could develop “ in reverse.” 
Combat . There seems to be no doubt that the eeratopsian horns were 
primarily, if not entirely, used as weapons. Whether they were purely 
defensive weapons, or whether they were also used in duels between mem- 
bers of the same species is not yet established, although Lull (3, page 22) 
cites important evidence for the latter view. In the crest the ceratopsians 
had a more or less effective shield for the vulnerable neck region, although 
I have pointed out above that this was not the primary function of that 
structure. Lull (3, page 22) cites with apparent approval the views of 
Nopcsa (4, page 69), who pictured the ceratopsians constantly presenting 
the armed head to the enemy by rotating the body horizontally about the 
fore quarters. This, no doubt, is the most advantageous manner for a 
quadruped to change front rapidly. In ceratopsians, however, the evidence 
of the limbs indicates that the hind quarters were incapable of much lateral 
movement, whereas the fore quarters could be quickly displaced simply by 
flexion of one limb and extension of the other. Therefore, we must re- 
• verse Nopcsa T s picture and imagine the embattled eeratopsian guarding 
itself by rapid shifts of the head and fore quarters to one side or the other, 
while the hind quarters remained relatively immobile. In a thrust, how- 
ever, it was the powerful hind limbs that drove the body forward. 
REFERENCES CITED 
1. Lull, R. S.: “Restoration of the Homed Dinosaur Diceratops” ; Am. Jour. Sci., 
vol. 20, pp. 42-422, PI. 14 (1905). 
2. —“The Cranial Musculature and! the Origin of the Frill in the Ceratopsian 
Dinosaurs ”; Am. Jour. Sci., vol. 25, pp. 307-3919, 10 text figs.. Pis. 1-3 (1908). 
3. “A Revision of the Ceratopeia or Homed Dinosaurs”; Mem. Peabody Mm 
^ Nat. Hist., vol. 3, pt. 3 (1933). 
4. Nopcsa, F.: “ Dinosaurierreste aus Siebenbiirgen V”; Geol. Hungarica, ser. pal., 
fasc. 4. (1929). 
5. Osawa, G.: “Beitrage zur Anatomie der Hatteria punctata”; Arch. Mikr. Anat. 
Entwicksl., Bd. 51, pp. 481-691 (1898). 
6. Romer, A, S.: “Crocodilian Pelvic Muscles and Their Avian and Reptilian Homolo- 
gues”; Bull. Am. Mus. Nat. Hist., vol. 48, art. 15 (1923). 
7. — “ The Pelvic Musculature of Omithischian Dinosaurs ” ; Acta Zoologica, vol. 8, 
pp. 225-275, 20 figs. (1927). 
8. Shufeldt, R. W.: “The Myology of the Raven”; Macmillan and Co. (1890). 
9. Sternberg, C. M.: “Homed Dinosaur Group in the National Museum of Canada.”; 
Can. Field-Nat., vol. 41, pp. 67-73, 2 pis. (1927). 
10. Tait, J„ and Brown, B,: “How the Ceratopsia Carried and Used Their Head”; 
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