282 



The maxillary was found in connection with mandibles of Ischyoclus 

 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 

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

 inner of the species of Ischyodus. Length, m .140; width, m .024: depth 

 (oblique), m .070. 



This species is readily distinguished from its congeners. 



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

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

 borough, from I. C. Voorhees. 



Leptomyltjs cookii, Cope. 



Proceedings of the American Philosophical Society, 1870, p. 384. 



Greensand of New Jersey, No, 5, near Mount Holly, Burlington County. 



EUMYLODUS, Leidy. 

 Eumylodus laqueatus, Leidy. 



Report of the United States Geological Survey, by P. V. Haydcu, vol. I, p. 309, 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 laqueatus, Leidy ; but differs 

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

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

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



Bkyactinus amorpiius, Cope. 



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

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

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

 exposes the posterior end of the apical column of dentine. Three other 



