282 



The maxillary was found in connection with mandibles of Ischyodus 

 mirificus, but does not pertain to them, and is only inferentially referred to 

 this species. The resemblance to the mandibles is very great. Its oblique 

 superior and outer face is greatly extended, while the inner is narrow and 

 vertical. The usual superior groove is present, and close to the edge of the 

 latter. The inferior border is quite thin. There are only two dentinal areas 

 present, and these are exceedingly small, representing the outer and anterior 

 inner of the species o{ Ischyodm. Length, 0™.140; width, 0'".024; depth 

 (oblique), 0'°.070. 



This species is readily distinguished from its congeners. 



From the greensand of New Jersey, No. 5 ; a mandible from Horners- 

 town, from Joliu C. Miers, and mandible and maxillary from near Barnes- 

 borough, from I. C. Voorhees. 



Leptomylus cookii. Cope. 



Proceedings of the Aiuericau Philosophical Society, 1870, \i. :!84. 



Grreensand of New Jersey, No, 5, near Mount Holly, Burlingtim County. 

 EUMYLODUS, Leidy. 



EuMYLODUS LAQUEATUS, Leidy. 



Re(iort of the Uuited States^Geological Survey, by F. V. Haydeu, vol. I, p. ;!0i), Plates XIX 

 and XXXVII. 



Cretaceous, near Columbus, Northern Mississippi. 



BRYACTINUS, Cope, genus novum. 



Represented by a bone of the jaws, either mandibular or premaxillary. 

 It resembles, in several respects, the Eumylodus Inquealus, Leidy ; but diifers 

 in having several dentinal areas exposed along the outer margin, and in having 

 the apical tube exposed at both extremities. From Ischyodus, it differs in 

 the same respects and the excavation of the posterior half of the inner face. 



BkYACTINUS AMORPIIUS, CopC. 



The section of the jaw is triangular; the base representing the grimling- 

 face, and not level, but, like both the others, slightly convex. The opposite 

 angular ridge only extends half (he length of the jaw, and then sinks, and 

 exposes the posterior end of (lie a|)ical column of dentine. Three other 



