398 ./?. S. Lull — Cranial Musculature in Dinosaurs. 



(fig-. 3) has perhaps the most Trieeratops-like crest, but the 

 culmination is seen in the male of the little Chameleo owenii 

 from Cameroon (fig. 10), as it not only has a fairly perfect frill 

 but three horns as well, one upon the nose and a pair above the 

 eyes precisely as in Triceratops. There is, however, this 

 distinction ; the horns in the chameleon are entirely epidermal, 

 having no bony horn cores, and are confined to the male, 

 whereas a hornless Triceratops has never been found. In 



Fig. 1Q. Chameleo owenii ; adapted from Meteaif. 



Chameleon they seem to be the result of sexual selection and 

 are certainly not for aggressive warfare in a creature which 

 moves with the utmost caution, while in Triceratops the 

 presence of efficient weapons in both sexes was an imperative 

 factor in the struggle for existence. 



Bibliography. 



1884. Dollo, L. : Cinquieme note sur les Dinosauriens de Bernissart. 

 Extrait du Bulletin dn Musee Royale d'hist. nat. de Belgique, T. iii, 

 pp. 136-146, pi. vi. 



1904. Lambe, L. M. : On the squamoso-parietal crest of the horned Dino- 

 saurs Centrosaurus apertus and Monoclonius canadensis from, the 

 Cretaceous of Alberta. Trans. Roy. Soc. Canada (2), vol. x, sect. iv. 



1905. Lull, R. S. : Restoration of the horned Dinosaur Diceratops ; this 

 Journal (4), vol. xx, p. 420. 



1908. Lull, R. S. : The Ceratopsia, Monograph xlix, U. S. Geol. Surv. , part 



ii (only). 

 1896. Marsh, O. C. : Dinosaurs of North America, 16th Ann. Rept. U. S. 



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 1870. Mivart, St.G. : On the Mythology of Chameleon parsoni. Proc. Zool. 



Soc. London, 1870, pp. 850-890. 

 1881. Parker, W. K. : On the Structure of the Skull in the Chameleons. 



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