THE CAMBRIDGE GREENSAND. 625 
no indications of facets for the attachment of sacral ribs, unless they 
be in the fractured and decomposed sides of the second sacral 
element. The other sacral fragment is smaller, and consists of the 
hinder portion of a vertebra with a flattened underside, which 
unites by a visible suture (fig. 6, 6) with the fourth sacral, which is 
1,5 inch long. At the junction of these two vertebre there 1s laterally 
a large flattened surface of 17 inch, and extended to the bases of the 
centrums, to which one of the principal sacral ribs was obviously 
attached. The fourth sacral is very narrow, measuring only 1 inch 
from side to side in the middle, and having well-rounded sides and 
a rounded base. Neither vertebra shows any portion of the neural 
canal; and the posterior face of the fourth, which seems to have 
become separated from the sacral vertebra next succeeding, was flat, 
small, subcircular, and hardly more than 1 inch in diameter (fig. 6, ¢). 
Caudal Vertebre.—The five caudal vertebrae are not consecutive. 
The two earliest (fig. 7) have the centrums with oblique articular 
Fig. 7.—Second Caudal Vertebra of Syngonosaurus macrocercus, 
nat. Size. 
B. Posterior view. 
