158 CRETACEOUS AND TERTIARY FISH. 



Trunk elongate-fusiform., and, like head, laterally com- 

 pressed. Mandible little prominent, with inner widely-spaced 

 series of large slender teeth, front largest, also marginal series 

 of minute teeth all nearly or completely solid. Premaxillary in 

 form of vertical lamina, deepest in front, tapering behind, with 

 uniserial small teeth. Maxillary long, slender, either finely 

 toothed or edentulous at oral edge. Palatine thickened, tumid, 

 with only one large tooth fixed at front end. Ectopterygoid ro- 

 bust, with single spaced series of large slender teeth, gradually 

 diminished in size backwards. No teeth barbed. Operculum 

 strengthened on inner side by ridge extending horizontally back 

 from point of suspension. Cranial roof with deep median longi- 

 tudinal depression, lateral and occipital margins ornamented like 

 other external bones, with ridges and tubercles of ganoine. 

 Branchiostegal rays about 12-16. Vertebrae 40^50, about half 

 caudal. Centra at least long as deep, constricted mesially, and 

 marked with small irregular longitudinal ridges. Rudimentary 

 dermal scutes not overlapping, in single median series between 

 occiput and dorsal and along course of lateral line. Pair of en- 

 larged hook-shaped dermal scutes at base of tail, one on either 

 side of caudal peduncle. All except foremost rays of each fin 

 finely divided distally, but none excessively elongated. No post- 

 clavicular plate. Dorsal and anal large, neither much longer than 

 deep, and former arising much before middle point of trunk, lat- 

 ter also far forwards. Posterior adipose dorsal. Caudal forked, 

 with curved fulcral rays and stout articulated undivided rays at 

 base both above and below. Pectoral large. Ventral much 

 smaller than pectoral, and far forward. 



About 30 species have been described. 



Enchodus ferox Leidy. 



Bnchodus ferox Leidy, Proc. Acad. Nat. Sci. Phila., 1855, p. 397. Greensand 



near Mount Holly, N. J. 

 Emmons, Man. Geol. Ed. 2, i860, p. 214, fig. 182 (no loc.) . 

 Cope, Rep. U. S. Geol. Surv. Terr., II, 1875, p. 277. (Below Greensand 



No. 5, New Jersey.) 

 Hay, Bull. Am. Mus. N. H., XIX, 1903, p. 68, fig. 50 (Cope's material). 

 Hussakof, Bull. Am. Mus. N. H., XXV, 1908, p. 72 (Cope's material). 



