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Dr. Francis Baron Nopcsa — British Dinosaurs. 



American Triceratops, the vertebras of the latter being much more 

 abbreviated and transversely expanded. The dorsal vertebrae of the 

 highly interesting Stegoceras and Stereocephalus are yet practically 

 unknown. 



Compared with Scelidosaurus and Stegosaurns there exists [a, 

 remarkable difference, for in the former the diapophyses are given 

 off" at a much lower point than in Polncanthns, while Stegosauru» 

 seems to exaggerate this elevation of the diapophyses which separates 

 Polacantlius from Scelidosaurus. In a future paper on Dacentunis 

 I intend to come back once more to this question, and I shall try 

 to show why this elevation of the neural arch (visible also in fossil 

 South American sloths) was developed. Here I only wish to 

 draw attention to the fact that in a recent paper (Ann. Mag. Nat. 

 Hist., 1904) Professor Seeley tries to explain this elevation by 

 the upward pressure of the lungs against the neural spines. 

 The anchylosis of the lumbar vertebrae, a unique feature among 

 Dinosaurs, strongly reminds one of the same character in Glyptodori, 



Fig. 1.— Dorsal vertebra of Polacantlius, posterior view. 

 ,, 2.— Dorsal vertebra, of Strnthiosnur/is, posterior view. 



and may be explained as subserving the very same purpose. 

 Hulke's description is equally satisfactory for the sacral as for the 

 lumbar region of the body. The inter-vertebral position of all 

 sacral ribs is, however, a fact worth while mentioning once more. 



There does not seem to exist any especial widening out of the 

 neural canal in the sacral region, as recorded for Stegoceras, and 

 also visible in Dacenlnrus (Omosauriis) . 



Concerning the caudal vertebrae, there is, first of all, the curious 

 fact to be noted, that while Fox originally mentioned 20 vertebrae 

 and I myself managed to count 19 distinct centra Hulke mentions 

 only 13, so that for some time 6 were apparently missing. 



As Hulke points out, the proximal caudal (Fig. o) are much 

 broader than high, and have, in consequence of the neural canal 

 being partly lodged in the centrum, a somewhat depressed heart- 

 shaped outline. At the same time they are much shorter than the 



