﻿GREAT OOLITE. 



31 



Fig. 1, 



cetiosaurian texture of the bone (PI. X, fig. 2, p ), as contrasted with the cancellated 

 structure in Botliriospondylus (PI. IX). The resemblance of this close but somewhat 

 coarse osseous tissue to that of cetaceous bone, especially in the larger Whales, and which 

 seems to characterise the whole skeleton of the present genus of gigantic saurians, might 

 well excuse the idea that the huge long bone first observed was cetaceous. 



The unbroken surface of the vertebra has a fine fibroid character ; the interrupted 

 lines affecting a longitudinal course on the centrum and a vertical one on the 

 neurapophysis. How far any exposure of the arch at the base of the spine may have 

 formed a part answering to the ' platform ' in the antecedent vertebra, and as in most 

 Dinosaurs, the broken state of the specimens does not allow of determination. 



Near the borders of the articular ends of the centrum, which are more or less 

 rubbed away, stronger sculpturing is indicated, as if in relation to ligamentous 

 attachments. 



The lower border of the lateral depression, /, is more obtuse, less definite, than in 

 Botliriospondylus (PI. VIII) ; the vertical convexity of the side of the centrum changes 

 in Cetiosaurus more gradually into the concavity of the depression. 



The sternum of Cetiosaurus longus is a transversely elliptical plate with an almost 

 flat, slightly undulate upper or inner surface 

 (fig. 1); 19 inches broad, 15 inches long, 

 1 inch to \\ inch thick, increasing to 2j 

 inches at the coracoid articular surfaces, 

 though, probably, the entire expanse of the 

 border here is not preserved. The hind 

 border shows prominences for the attachment 

 of three pairs of sternal ribs, the hindmost 

 pair in contact, as in Monitor niloticus. 



In this Lizard the sternum has a rhom- 

 boidal form, with a low median ridge on the 

 outer or under surface, a deep hollow 

 on the opposite surface, and considerable 

 thickening of the articulations for the cora- 

 coids. Were these bones fully ossified in that 

 Lizard they would correspond in breadth with 

 those of Cetiosaurus ; there are, however, 

 two tracts retaining the primitive sclerous 

 state, and an antero-medial part which has not gone beyond that of gristle, in the coracoid 

 of the recent saurian. We have, therefore, in Cetiosaurus, as in some other ancient 

 saurians, especially Binosauria, a degree of lacertian structure combined with a crocodilian 

 advance of vertebral and concomitant cardiac and pulmonic structures. 



The scapula of Cetiosaurus (fig. 2) is more crocodilian than lacertian in its 



T,<' 



Sternum, Cetiosaurus longus, -j^th nat. size. (Phps., ' 

 ' Geol. of Oxford,' part of diagr. xcviii, p. 268.) 



