182 DINOSAURS OF NORTH AMERICA. 



axis are not auchylosed together, and the elements of the atlas are 

 separate (PI. XXXI). 



The dorsal vertebrae are distinctly opisthocoelous. The posterior dor- 

 sals have elongated transverse neural spines, and have deep cavities 

 in the sides. An anterior dorsal is shown iu figs. 31-33. p. 1S1. There 

 are four vertebrae iu the sacrum, all with cavities in the centra. Their 

 transverse processes, or sacral ribs, are vertical plates with expanded 

 ends. The anterior caudal vertebras are plano-concave, and nearly or 

 quite solid. The tail was elongated, and the chevrons are similar to 

 those in crocodiles (PI. XXXIX). The vertebra; of Morosaurus are 

 represented on Pis. XXXI-XXXIV. 



THE FORE LIMBS. 



The scapula is elongated and very large, and the shaft has a promi- 

 nent anterior projection. The coracoid is small, suboval in outline, 

 and has the usual foramen near its upper border. These two bones 

 are well represented in PI. XIX, nearly in the relative position in 

 which they were found. The humerus is very large and massive, and 

 its radial crest prominent. This bone is nearly solid, and its ends 

 were rough and well covered with cartilage. This is true, also, of all 



Fig. 34.— Cast of neural cavity in sacrum of Morosaurus lentus Mar.sh; side view. One-fourth nat- 

 ural size. 



i, i\ i", i"\ intervertebral foramina; v, v', v", v'", cavities in first, second, third, and fourth sacral 

 vertebra-. 



the large limb bones in this genus. The radius and ulna are nearly 

 equal in size. The carpal bones are separate aud quite short. The 

 live metacarpals are elongated, and the first is the stoutest. The toes 

 were thick, and the ungual phalanges were evidently covered with hoofs. 

 In PI. XXXVIII, fig. 1, the restoration of the scapular arch and entire 

 fore limb of one species of Morosaurus well illustrates this part of the 

 skeleton. 



THE PELVIS. 



The pelvic bones are distinct from each other and from the sacrum. 

 The ilium is short and massive, and shows on its inner side only slight 

 indications of its attachment to the sacrum. More than half the 

 acetabulum is formed by the ilium, which sends down in front a strong 

 process for union with the pubis, and a smaller one behind to join the 

 ischium (PI. XXXV, fig. 1, a aud b). The acetabulum is completed 

 below by the pubis and ischium. The pubis is large and stout, and 



