204 Prof. R. Owen on the Occurrence 



tive of the bifurcation of the proximal end of the rib into a 

 a capitular and a tubercular articulating process " *. 



Of " the supposed cervical vertebra " from Dakota, Prof. 

 Cope writes : — " Near the anterior extremity a short robust 

 parapophysis has its origin, from which it extends outwards 

 and downwards, and soon terminates in a truncate extremity 

 which presents downwards. A deep fossa occupies its upper 

 base ; and above this a deep linear foramen extends throughout 

 the greater part of the length of the centrum." 



Of the dorsal vertebrae Prof. Cope writes : — " The widely 

 extended diapophyses support the rib-articulations ; and there 

 are no capitular articular facets on the centra ; but such are 

 found on the basal region of the diapophyses in some ver- 

 tebra} "t 



So, likewise, in a vertebra of Chondrosteosaurus which had 

 "come from a more posterior part of the column," I note that 

 " the parapophysis " (or " capitular articular facet ") " had 

 disappeared, at least from the position from which it projects 

 in the subject of plate ii." J 



Thus there is correspondence of the fossils compared in 

 characters of the rib-joints, as in those of the terminal articu- 

 lations and of the osseous texture. 



4. Parapophysis. 



But this correspondence is further carried oat in the shape, 

 direction, and position of the parapophyses of the cervical or 

 anterior trunk-vertebrae. In CAonc/rosieosawrMS " the fore part 

 of the base of the process occupies the lower vertical half of 

 the centrum, commencing at some distance from the hind 

 end, and terminating very near the beginning of the anterior 

 articular ball" §. 



The close similarity in proportion and position of the para- 

 pophyses (p) is exemplified in PI. X. fig. 1, from the re- 

 duced view given in my ' Monograph ' of 1876, pl.ii. fig. 2 — 

 and in that (PL X. fig. 3) copied from fig. a, pi. i., appended 

 by Prof. Cope to the paper " On the Vertebrata of the Dakota 

 Epoch of Colorado," in the ' Proceedings of the American 

 Philosophical Society,' no. 100, vol. xvii. 1877. 



5. Fossce of Centrum. 



To come to minor characters. In Chondrosteosaurus " the 

 whole side of the centrum is occupied by a deep oblong de- 



• Monogr. cited, p. 5. t Pal. Bull. no. 25, 1877, p. 7. 



X Monogr. cited, p. 7. § Ibid. p. 7. 



