156 



MR. E. LYDEKKER ON DIN0SAT7RIAN VERTEBRA 



11. On certain Dinosattrian Vertebra from the Cretaceous of India 

 and the Isle oe Wight. By R. Ltdekker, Esq., B.A., F.G.S., 

 &c. (Bead January 12, 1887.) 



In the year 1877 I published * a prelimiuary description of certain 

 Dinosaurian remains obtained from the Lameta group of the 

 Jabalpur district of India, to which I applied the name of Titano- 

 saurus indicus. The Lameta beds, it may be observed, have been 

 usually referred to the Middle Cretaceous (Upper Greensand), but 

 later observations indicate that they may be of somewhat newer age. 

 The remains on which the genus was founded are preserved in the 

 Indian Museum, Calcutta, and comprise an imperfect femur, and a 

 considerable number of late caudal vertebras, together with one 

 imperfect vertebral centrum from an earlier part of the series. In 

 a later memoir f I gave figures of some of the more important of 

 these specimens, and came to the conclusion that the vertebrae in- 

 dicated two species, for the second of which I proposed the name of 

 T. Blanfordi, adding the proviso that this form might eventually 

 turn out to be generically distinct from T. indicus. 



Both these types of late caudal vertebrae are characterized by 

 their strongly procoelous centra, to the anterior half of which the 

 anchylosed neural arch is confined ; and in the one perfect specimen 

 of T. indicus the arch carries two well-marked processes, one of 

 which is directed anteriorly and the other posteriorly. The pre- 

 axial process is bifurcated anteriorly, and bears a pair of prezy- 

 gapophysial facets ; while the hinder one, which (judging from the 

 caudal vertebrae of the Sperm-Whale and of certain other Dinosaurs) 

 I think includes the representative of the neural spine J, is single, 

 and carries the postzygapophyses. In T. indicus the haemal aspect 

 of the bone presents two pairs of Y-shaped ridges, on the extremities 

 of each of which are a pair of well-defined facets for the attach- 

 ment of chevron-bones, which look directly downwards ; while the 

 centrum is relatively short, with its haemal surface placed nearly 

 at right angles to the lateral surfaces and characterized by its 

 extreme lateral compression. In the form to which the name T. 

 Blanfordi has been applied the centrum is larger and subcylindrical, 

 and the haemal and lateral surfaces are not distinctly differentiated 

 from one another, the ridges on the former surface are not present, 

 and the facets for chevron-bones are either very indistinct or totally 

 wanting. 



These two types of vertebrae appeared to me to come nearest to 

 those of Cetiosaurus and the so-called Pdorosaurus of the English 



* Eec. Geol. Surv. Ind. vol. x. p. 38 (1877). One of the specimens had been 

 previously described and figured (without name) in Falconer's 'Palasontological 

 Memoirs,' vol. i. p. 418, pi. xxxiv. figs. 3-5. 



t ' Palseontologia Indica ' (Mem. Geol. Surv. Ind.). ser. 4, vol. i. pt. 3, p. 20, 

 pis. iv. & v. (1879). 



| Many writers adopt a different view in describing analogous specimens. 



