146 



University of California Publications. 



[Geology 



of the specimens described in this paper resemble the crossop- 

 teiygian ganoids and may be referred to the family, Megalich- 

 thyidae,- on account of the tooth structure, the variation in size 

 of the teeth, and the structure of the dermal plates. 



The teeth which have been obtained are conical, with a pulp 

 cavity of which the walls are vertically folded towards the base. 3 



Figs. 1 anil 2 natural size; figs. 3, 4, and 5 one-half natural size. 



They are firmly set in the bone, are close together, and all were 

 apparently functional at the same time. There is a great varia- 

 tion in size which is a character common with Megalichthys 

 hibbcrti as described by Dr. Hibbert. 4 The basal portions of the 



2 Hay, O. P., Catlg. of Fos. Vert. North Anier., p. 359. 

 5 Woodward, A. S., Catlg. Fos. Fish. Brit. Mus. PI. II. 

 4 Trans. Roy. Soc. Edinb., XIII, pp. 169-282. PL V-XIII. 



