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PEOCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 77 



nating on the posterior half of the centrum extending outward, 

 strongly backward, and slightly upward. These processes are 

 T-shaped in cross section. The first pair may have abutted against 

 the posterior border of the ilium as in N odosaurus. 



Measurements 



Mm. 



Greatest len^itb of sacral series 725 



Greatest width across sacral ribs 540 



Caudal vertebrae. There are 11 free caudal vertebrae present 

 but these do not form a continuous series, at least five being neces- 

 sary to fill the gaps in addition to an unknown number missing from 

 the distal end. In the complete caudal series of Dyoplosaurus^ 

 Parks ^^ recognized no less than 23 vertebrae, and it seems quite prob- 

 able that the animal here described may have had an equal number. 



Figure 12. — Third caudal vertebra oi Palaeoscincus rugosidens. 

 Type. No. 11868, U.S.N.M. A, Lailr^l vie\\ , B, Anterior view. 

 Both figures about one-third natural size 



The caudal centra are short, articular faces wider than high, amphi- 

 coelous, and having the notochordal protuberances at the center as 

 in the presacrals. The sides of the centra are deeply excavated in 

 those vertebrae having transverse processes, but more moderately so 

 posteriorly. A single vertebra from the region posterior to the mid- 

 dle of the tail is considerably longer than any that precede it. 



The transverse processes are long, horizontal, and, excepting the 

 anterior three which articulate in part with the side of the arch, 

 all spring from the superior side of the centrum; posteriorly their 

 length decreases regularly. The transverse processes of the first 

 three have slightly expanded ends (fig. 12). Those of the second 

 caudal are directly slightly forward and are in contact with those 

 of the first on the outer border where there is a rugose roughening. 

 Similarly, number one was in contact with the last sacro-caudal. 



"Univ. Toronto Studies, Geol. ser., 1924, pp. 14-16. 



