106 



University of 



California. 



[Vol. 3 



Cymbospondylus petrinus Leidy. 



Pl. 16, PIGS. 4 AND 5. 



The second species, consisting 1 of the greater part of three 

 centra with portions of two arches, is desei'ibed by Leidy as 

 follows : 



"They apparently indicate a much larger species of the same 

 genus as the former, the vertebral body having the same form. 

 The sides of the articular funnels are convex outwardly from the 

 centre, which deepen more rapidly at the inner third of the 

 surface. One specimen retains the neural arch without its spine, 

 and a short, robust, costal process, extending from near the 

 bottom of the arch almost half the depth of the body. A second 

 vertebra is singularly distorted, apparently as if the bone had 

 been in a plastic condition." 



From Humboldt, Nevada. 



After uncovering the costal processes of the vertebra? of this 

 species they were seen to be essentially the same as those of 

 C. piscosus. The centra are, however, much shorter than in the 

 type species, the ratio of length to height being 1:2.35. The 

 form of the anterior and posterior surfaces of the centra is also 

 very different. Instead of sloping sharply from margin to 

 centre, the concave surfaces slope gently from the periphery for 

 about two-thirds of the distance to the centre and then drop 

 down very rapidly to the middle, making a central depression 

 which almost meets a similar one on the opposite side. 



The vertebrae present are evidently middle dorsals of a species 

 much larger than piscosus. 



The measurements of a somewhat distorted centrum are as 

 follows : 



Height of centrum 87 mm 



Width " 87 



Length " : 37 



Cymbospondylus (?) grandis Leidy. 

 Pl. 16, fig. 3. 



Chonespondylus grandis Leidy. Proc. Phila. Acad. Sc., Vol. 20, 1868, p. 178. 



A third species, based on a fragment of a caudal from Star 

 Canon, Humboldt Co., was made the type of a new genus, 



