DINOSAURS. 7 



pubis with only a pre-pubic braiicli, meeting- its fellow in the 

 middle line, two-rooted teeth implanted in sockets, and 

 plantigrade, five-toed limbs. Bony plates are dotted over 

 the skin. Triceratops, of the North American Cretaceous, is 

 a well-known iy^Q. 



Casts of specimens of a few remains of different members of [the 

 group are exhibited in "Wall-Case No. 4, in which there is also a 

 miniature restoration of the species known as Diplodociis (41)- Of the 



Fig. 6. 



Side view of Skull of a Sauropod Dinosaur [Diplodocus) , from the Upper 

 Jurassic strata of Colorado, U.S.A. ; one-sixth nat. size. The cleft at the 

 summit of the head is the nostril, and the large round vacuity the eye- 

 socket. The diminutive brain-case is behind and partly between the 

 eye-sockets. (No. 47-) 



latter animal, the cast of an entire skeleton, the gift of Mr. Andi'ew 

 Carnegie, is mounted in the middle of the gallery {see Frontispiece). 



Diplodocus is a representative of the Sauropod section, which 

 includes the largest of all land-Reptiles, and flourished during the 

 Jurassic and Lower Cretaceous epochs, that is to say, Avhen the 

 Oolites, Wealden, and Greensands were being deposited. These 

 Reptiles walked on all fours ; but, despite the light construction of 

 the neck and trunk-vertebrae, w^ere probably too heavy for much 

 activity on land, and dwelt near the sea or lakes, w'here they lived in 

 the shallows and fed on water-plants ; the long neck and the position 

 of the nostrils at the summit of the skull enabling them to breathe 

 when wading at considerable depths. Brontosaiirus and Atlantosanrus 



