Type of the Oenus Massospondylus. 107 



vertical truncation of the anterior parts of the sides, so as to 

 leave only a narrow vertical median strip of the centrum to 

 meet the sacral vertebrae, which was placed in front. This is 

 due to the encroachment of the sacral ribs, which were situate 

 at the junction of the two vertebrae, as in most of the Old- World 

 Saurischia and as in D enter osaurus. The encroachment of 

 the sacral ribs, no less than the short length of the centrum, 

 indicates that the sacrum was consolidated early in life. The 

 centrum is less than 2 inches long, l/o inch deep, l/o inch 

 wide. 



Caudal Vertehrce. (Fig. 3.) 



The vertebrse which have been regarded as caudal all retain 

 the transverse processes above the level of the base of the 

 neural canal. The centrum (fig. 3) has a conspicuous lateral 

 compression in the middle, rounded base, and large facets for 

 the chevron-bones. The articular surface is conically concave 



IKiglit side of centrum, early caudal vertebra, \ nat. size. 

 No. 338 reversed, 



in front and more flattened behind, with a rather small neural 

 canal and depressed neural arch, with the neural spine inclined 

 backward. The spine diminishes in height as the vertebrse 

 diminish in size. The caudal vertebrae are referable to more 

 than one individual. 



Pelvis. 



Sir B,. Owen identified the ilium 358 and the ischium 359. 

 He remarks that the left iUum terminates anteriorly in a 

 short obtuse process in advance of the acetabulum ; but it is 

 supposed that its anterior part has been broken away, and the 

 bone in form and proportions was said (1854) to most resemble 

 the iliac bone of Iguanodon. Notvvitlistanding some uncer- 

 tainty in determination of the ilium in allied animals in !Sir R. 

 Owen's later writings, these remarks appear to indicate that the 

 pelvic affinities of the animal were rightly appreciated. 



