OOLITIC DINOSAURS. 



583 



beyond ; but the neurapophysis soon shows, as it rises, the ' short antero-posterior 

 extent/ which is among the characteristics of the genus. One advantage of the 

 fractures, which must otherwise have been got by sections, is the demonstration of the 

 cetiosaurian texture of the bone (PI. 76, fig. 2, p). 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 

 neurapopliysis. 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 relatiou to ligamentous 

 attachments. 



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

 BotJiriospondj/lus (PL 03, fig. 1) ; the vertical convexity of the side of the centrum changes 

 in Cetiosaurus more gradually into the concavity of the depression. 



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

 fiat, slightly undulate upper or inner smface 

 (fig. 2); 19 inches broad, 15 inches long, 

 1 inch 10 \\ inch thick, increasing to 2^ 

 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, r, r, 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. AVe have, therefore, in Cetiosaurus, as in some other ancient 



11/^ 



Fig. 2. 



Sternum, Cetiosaurus longus, \^i^ nat. size. (Phps., 

 ' Geol. of Oxford,' part of diagr. xcviii, p. 208.) 



