O. C. Marsh—New Lamily of Dinosaurs. 165 
‘its greatest depth is at the symphysis. The articular, angular, 
and subangular bones are well developed, but the coronary and 
splenial appear to be small. 
THE TEETH. 
edentulous. The teeth are entirely confined to the front of the 
jaws (Plate III, figure 1), and those in use were inserted in 
slender. The crowns are more or less compressed transversely, 
. . . he 
“oto rapidly replaced, as they wear out or are lost, by a 
ig of successional teeth, more numerous than is usual in 
Soe oo Plate IV, figure 3, represents a transverse sec- 
] D through the maxillary, just behind the fourth tooth. The 
ster is shown in place (1), and below it is a series of five im- 
Emirs teeth (2 to 6), in various stages of development, prepar- — 
lik 10 take its place. These successional teeth are lodged in a 
ti 8© cavity (c), which extends through the whole dental por- 
'on of the maxillary. The succession is also similar in the 
Premaxillary teeth, and in those of the lower jaws. 
THE VERTEBRA. 
The vertebral column of Diplodocus, so far as at present 
Own, may be readily distinguished from that of the other 
n ag 
Sauropoda by both the centra and chevrons of the caudais, ~ 
* This Journal, xix, p. 255, March, 1880. 
