215 



lary and dentary bones, one foramen 1o each tooth. The alveolae are confluent 



as they approach this margin. 



There are three vertebra;, which present two pairs of deep longitudinal 



grooves, viz, two on each side, two on the inferior, and two on the superior 



face of the bone ; the last receives the basal articulation of the hsemapophyses. 



The centra are crushed. Their measurements, with those of the jaws, are as 



follows : 



Measurements. 



II. 



Length of the centrum 0. 025 



Long diameter (crushed) 0. 035 



Short diameter (crushed) 0. 0175 



Depth of the maxillary bono anteriorly 0. 031 



Depth of the dentary bone anteriorly ^ 0. 015 



Length of tho crown of tho inferior tooth 0. 00G 



Length of tho crown of tho superior tooth 0. C04C 



Number of inferior teeth in m .01, 3 ; number of superior teeth in m .01, 4.5. 



The vertebrae are about as large as those of a fully-grown " drum-fish," 

 Pogonias. 



From the yellow chalk of the Upper Cretaceous of Kansas, found on the 

 Solomon or Nepaholla River, Kansas, at a point one hundred and sixty miles 

 above its mouth, and in Trego and Rooks Counties, by Prof. 13. F. Mudge, 

 professor of natural science in the State Agricultural College of Kansas. 



SAUROCEPHALUS, Harlan. 



Leidy has pointed out the mode of implantation of the teeth in the 

 typical species of this genus. The mode of succession of the teeth has not 

 yet been indicated, but is well displayed in a specimen of the jaw of S. ara- 

 pahovius, Cope. It is known from Harlan's description that a large foramen 

 issues on the inner wall of the jaw, opposite each root. The fractured ends 

 of the specimen exhibit the course of the canal which issues at this foramen. 

 It turns abruptly downward between the inner wall of the jaw and the fang 

 of the functional tooth, and not far from the foramen. Its course is inter- 

 rupted by the crown of the successional tooth. This is situated obliquely as 

 regards the long axis of the jaw. 



It is thus plain that the successional appearance of teeth is different in this 

 genus from what I have described in Portheus and Ichthyodectes. In them, 

 the foramen is wanting, and the young crown rises within the pulp-cavity of 

 the functional teeth, as in the Crocodilia. In this genus, on the other hand. 



