168 



broad, smoath band separates the edge of the ball from the surfaces of the 

 centrum adjacent. The latter are rather finely striate-ridged from the edge 

 of this band. The inferior outline of the centrum is strongly concave, and, 

 with two venous foramina, separated by a wide interval. The basis of the 

 diapophysis on a lumbar is very broad, measuring more than half the length 

 of the centrum. In general characters, this lumbar resembles the dorsal, 

 including the emargination for the neural canal, but is shortened in relation to 

 its length. The depressed form of the lumbar centra gives place gradually 

 on the caudals to a more elevated pentagonal outline, which is still more 

 reduced in width in more posterior regions. The haemal arches are articu- 

 lated on the anterior caudals to slightly elevated bases ; on the more pos- 

 terior, the bases are reduced in height and more widely and deeply exca- 

 vated. I have not seen the most distal caudals, and hence cannot determine 

 whether their chevron-bones articulate in pits, as is the case with those of L. 

 perlatus, L. proriger, etc. On a caudal, where the depth of the centrum a 

 little exceeds the transverse diameter, the diapophysis has become narrow 

 and thick. The excavation for the neural canal is strongly marked on the 

 more anterior caudal. The smooth border of the articular ball is here narrow, 

 and the superficial rugae are fine, and confined to the anterior part of the 



centrum. 



Measurements. 



M. 



Transverse diameter of the ball of tho posterior dorsal 0. 144 



Venical diameter of the ball of the posterior dorsal 0.097 



Vertical diameter of the anterior caudal 0. 0J4 



Transverse diameter of the aDterior caudal 0. 107 



Length of the centrum of the caudal ._ 0.071 



Transverse diameter of the neural canal 0.0145 



Transverse diameter of the basis of the diapophysis 0. 032 



Transverse diameter of the basis of the diapophysis of a more distal caudal 0.0273 



Longitudinal diameter of the chevron articulation of the caudal 0.023 



Length of tho centrum 0.008 



Depth of the ball of the centrum 0.003 



Width of the ball of the centrum 0.091 



Length of the ceutrum of a lumbar 0. 106 



Width of the articular ball 0.125 



The characters of the Fort Wallace saurian are as follows : 

 The fronto-nasal septum is convex in transverse section. The maxillary 

 bone is much attenuated anteriorly, and supports thirteen teeth. The ramus 

 mandibidi is light and slender; the angle is quite produced, and the median 

 articulation indicates considerable mobility. The palatine bones are narrower 

 than in any of the species previously described. They are deeply notched 



