HOLOCEPHAU. 



137 



Leptomylus cookii Cope. 



Leptomylus cookii Cope, Proc. Amer. Philos. Soc. Phila., XI, 1870, p. 384. 



Near Mount Holly, Burlington Co., TV. /. Greensand No. 5. 

 Cope, Rep. U. S. Geol. Surv. Terr, II, 1875. p. 282. (Near Mount Holly, 



Burlington Co, N. J. Greensand No. 5.) 

 Leptomylus cooki Hussakof. Bull. Amer. Mus. N. H, XXV, igo8, p. 41. 



PI. 2, figs. 8-9 (type). 



Mandibular with posterior portion curved out from symphy- 

 seal, latter much compressed and moderately prolonged with 

 inner face quite concave, posteriorly outer face also slightly con- 

 cave. A single obtuse external crest descends gradually to plane 



Fig. 85. — Leptomylus cookii Cope. (Type, from Hussakof.) 



of beak, presenting no dentinal area. A single small oval area 

 represents internal, lies along inner margin and latter much 

 thickened, rolled over inwards and symphyseal face very narrow. 

 End of beak (broken away) in section shows no inferior plate- 

 like column, but a round column, which issues on upper surface 

 of beak behind apex. Length nearly 70 mm. (From Cope.) 



Cope says the apical dentinal column distinguished it from 

 L. densus, in which no such column exists. He also says at hind 

 fractured section of jaw apical column is seen, while internal 

 dentinal area not, latter occupying only a pocket, not a column. 

 The species is like Bdaphodon solididus in the apical column, 



