22 FOSSIL REPTILIA OF THE 



Streptospondylus major, Owen. Tab. V, VI. 



The vertebra; so named, in the British Museum, and in that of the late Mr. Saull, 

 F.G.S., now transferred to tlie Literary Institution, Aldersgate Street, London, have 

 belonged to the region of tlie neck, or fore-part of the back, and were obtained from 

 the Wealden formation of three localities, viz., Tilgate Forest, in Sussex ; Culver Cliff, 

 Isle of Wight ; and Brook Point, Isle of Wighr. They differ from the convexo- 

 concave vertebrae of Streptospondylus Cuvieri, from the Lower Oolite and Lias, in their 

 much larger size, and in the absence of the deep pit behind the costal facet. The 

 converging, buttress-like ridges on the sides of the neural arch appear to be developed 

 only in the anteriorly convex vertebrse of the dorsal re2;ion (Tab. VI, fis;. 5, n, b). 



Cervical vertebra. Tab. V, figs. 1 and 2. Tab. VI, figs. 1, 2, and 3. 



The cervical vertebra (Tab. V, figs. 1 and 2) measures six inches in length. * The 

 anterior end of this vertebra is determined by the aspect and position of the 

 zygapophysis (ib. z), which, as its articular surface looks obliquely upward and inward, 

 and is on a lower level than the oppositely turned process (z), must be the anterior 

 one. The corresponding extremity of the centrum (ib. b) is convex ; the opposite 

 extremity, which is somewhat overhung by the higher placed posterior zygapophyses 

 {z'), is concave, as shown in fig. 2, c. The whole vertebra is a little crushed obliquely. 

 The fore part of the centrum is further indicated by the position of the parapophysis 

 (ib. figs. 1 and 2, p) or transverse process for the articulation of the head of the rib ; at 

 least, according to the analogy of the Crocodilia, in which it comes off nearer the anterior 

 than the posterior end of the centrum * Beneath the parapophysis (p) the sides 

 of the centrum are concave, and converge downward to a broad ridge (Tab. VI, 

 fig. 2, h), which terminates (at h) the anterior part of the lower surface of the vertebra, 

 and corresponds with the hypapophysis given off" from that part in the cervical 

 vertebrae of the Crocodile. f A second concavity, at the upper part of the side of the 

 body, separates the parapophysis from the base of the neural arch ; from which a 

 diapophysis (upper transverse process) is developed for the attachment of the tubercle 

 of the rib. The diapophysis (Tab. V, fig. 1 , d) comes off from the under and outer side of 

 the anterior zygapophysis (ib. z). The articular facet of the latter process presents a full, 

 oval figure ; it is slightly raised at its outer part from the iiorizontal position. There 



* See ' Monograph on the Heptiha of the London Clay,' 18.50, t. ix, fig. 3, p : {Croco</ilus Hastiinjsia). 

 t lb., figs. 2 and 1. 



