32 



The position of this genus was not definitely determined, but its author considered 

 that the structure of a proximal limb bone, and the form of the diapoi>hyses of the verte- 

 brae referred it with much probability to the Urodela, and that the biconcave centra 

 placed it nearest to the Ambbjstnmida:. Also that other structural points indicated a 

 family different from any of those now living. 



A small right maxilla of which, two views are given (plate XY, figs. 16 and 17) is of 

 interest. It is almost perfect anteriorly. Its upper border comes to a sharp edge, from 

 which posteriorly a small fragment has been broken off, as indicated in the figure. A 

 ridge extends the length of the bone on the inner side at about mid-height at the centre 

 but curving downward to near the lower margin in front. Posteriorly two sutural sur- 

 faces occur, one on the inner side in continuance of the ridge, the other emargiuates the 

 upper border. Between these two surfaces the bone is shallowly excavated. Six large 

 foramina occur in a line at about mid-height in the anterior half of the outer surface. 

 The lower border of the maxilla is broad and bears eight subquadrately elliptical tooth- 

 bases with their greater diameters transverse to the length of the jaw. Small foraminal 

 openings occur encircling the outer surface of the tooth-bases. Teeth have been lost from 

 the jaw leaving shallowly depressed interspaces. 



The relationship of this bone is not clearly understood, but it is for the present asso- 

 ciated with Scapherpeton tectum. It occurred with and is of the same colour and texture 

 as the vertebrae of that species. 



REPTILIA. 



SADROPTERYGIA. 



PLESIOSAUEIDiE. 



CiMOLiASAURUS, Leidy. 



CiMOLlASAURUS MAGNUS, Leidy. 



Cimoliasaurus maynus, Leidy. 1852. Proc. Acad. Nat. Sci. Philadel., vol. v, p. 325, and ibid, 1854 

 vol. vii, p. J2, pi. II, figs. 4-6. 



Cimoliasanrus magnus, Leidy. 1865. Cretaceous Reptiles of the United States, p. 25, pi. v, figs 

 13-19 and pi. vi, (Smithsonian Contr. to Knowledge, vol. xiv). 



Fourteen cervical vertebrae, found within a limited space and probably belonging to 

 one individual, are referred to this species ; they form a tolerably complete series with a 

 gradual increase in size from front to back. 



These vertebrae agree with those of the type species in form but are smaller. 



The centra may be described as shorter than broad, with concave sides and lower 

 surface, articular faces ellipsoidal, sligthly concave with angular margins, costal facet 

 placed low on the sides. Neural arches in all the specimens, broken off, except in one, 

 apparently a late cervical, in which the basal part on one side is preserved, shov,ung the 



