HOLOCEPHALI. 



12: 



Edaphodon solidulus (Cope). 



Ischyodus solidulus Cope, Proc. Am. Philos. Soc. Phila., XI, 1867, p. 244. 



Hornerstozvn, Monmouth Co., N. J. Greensand No. 5. 

 Diphrissa solidula Cope, Rep. U. S. Geol. Surv. Terr., II, 1875, p. 283. 



(Hornerstown, N. J. Greensand No. 5.) 

 Edaphodon solidulus Hussakof, Bull. Amer. Mus. N. H., XXV, 1908, p. 39, 



PI. 2, figs. 1-2 (type). 



Mandibular compressed, rather deep, or depth about half its 

 length. No distinct external crests. Terminal area of beak 

 forms round extremity of a narrow column. Inner and outer 

 margins, anterior to large area, of equal elevation, regularly 

 curved outwards without angulation. No anterior outer den- 



Fig. yy. — Edaphodon solidulus (Cope). (Type, from Hussakof.) 



tinal area. Posterior outer dentinal area very small and faces 

 inwards from gradual elevation of outer superior margin. Inner 

 area very large, undivided, accompanied on inner margin by a 

 slender column which issues in posterior corner of symphyseal 

 plane. Length (restored) about 64 mm. (From Cope.) 



This species was made the basis of a separate genus by Cope. 

 The large inner area of dentinal tubules, with a terminal one is- 

 suing near the apex, and only a single small external dentinal 

 area were the chief characters he advanced. However, I accept 

 Hay's action in merging Diphrissa with Edaphodon. 



