288 



A maxillary bone accompanying the mandible is characterized by the 

 small size and posterior position of the anterior area, so that the bone appears 

 to be more produced. The posterior areas are large. 



Grreensand of No. 5 ; from Birmingham, New Jersey ; discovered by 

 Jnd,son C. Gfaskill, of that place. 



IsCHYODUS l.ATEEIGERUS, Cope. 



Proceedings of the American Philosophical Society, 1869, 243. 



Grreensand of No. 5, from Hornerstown, New Jersey; John C. Miers. 

 A very distinct species, not obtained since the discovery of the type. 



ISCHYODUS SMOCKII, Cope. 



Proceedings of the Boston Society of Natural History, 1809, p. 316. 



A well-marked species from the same horizon as the preceding. Several 

 individuals have been obtained from Mr. Miers's marl-pits at Hornerstown, 

 New Jersey. 



ISCHYODUS EOC/ENUS, Cope. 



Represented by parts of three individuals from the Eocene greensand 

 of Farmingdale, Monmouth County, New Jersey. One of these includes 

 the premaxillary and maxillary ; another, the mandible. Their size is simi- 

 lar, and they were taken from the same excavations, but at different times. 

 It is, therefore, uncertain whether they all belong to the same species, but it 

 is probable. 



The mandible may be selected as the type. The inner and posterior 

 oulcr areas are unfortunately broken away. The outer border of the beak rises 

 abruptly to a considerable elevation, which supports the anterior outer area. 

 The latter is oval, and well within the border; it is cut off at its posterior 

 portion, but in advance of the position of the inner area. The terminal col- 

 umn is laminar, and extends well back on the outer edge of the beak. The 

 outer face of the jaw is uniformly convex to the anterior outer area, and the 

 apex is transverse, not compressed. The symphyseal face is not well marked. 



Measurements. 



Length to the anterior outer area 0. 050 



Depth at the anterior outer area 0. 040 



Will til at the anterior outer area 0.028 



Width at the middle of the beak 0.018 



The areas of the maxillary are larp;e and elongate, but not on elevated 

 bases, as in /. smockii. The external face of the premaxillary is smooth; the 



