286 



iiiirrow, and cxiciuls n Hi lie anterior to the anterior liordcr of the anterior 

 outer The apex oi' the jaw is obtuse, and the terminal area is on its 

 superior aspect, is oval, and continues as the edge of a lamina along the outer 

 margin of the beak. There is no syraphyseal plane, and the whole jaw is 

 much compressed and narrowed. It has much the form of that of Lepfo- 

 mylus forfex, and approaches the /. lafciigenis. 



Measurements, . 



M. 



Loiigth of tbo fragment (total) 0. 070 



Depth behind 0.080 



Depth at the posterior outer area 0. ()(>4 



Depth at the anterior outer area 0. 04 1 



Deptli at the inner area 0. OH 



Depth of the inner face behintl 0.027 



Width at the inner area 0.018 



Width behind at the inner angle 0. 021 



Width l>ebind near the snmniit i'. 1)1.5 



Hornerstown, New Jersey. Greensand ot No. h. 



ISCIIYODUS TRIPARTITU.-i, Cope. 



/. mirificiis, "Leidy," Cope, Proceedings of the Boston Society of Natural History, 18G9, p. 

 314, not of Leidy. 



This species was embraced in the specimens mentioned l>y Professor 

 Leidy as having furnished the type of iiis 1. 7nirificus; and, as his tirst descrip- 

 tion does not specify to whicli of them he referred, I had supposed tliat those 

 belonging to the present species were the ones described. As Dr. Leidy has 

 subsequently selected a different one as his type (in Report of Hayden's 

 United States Geological Survey), it remains to give the present ChimaM-oid 

 a new appellation. 



The /. tripnrtUus is the largest of the American species of the genus, 

 and is not uncommon in the greensand of No. 5. The tripartite division of 

 th(^ imier area is a prominent feature : tiic three columns are united at their 

 adjacent borders: and tiie outer is more than twice as large as either of the 

 two interior ones. The latter are separated froui the inner angle of the jaw 

 l)y an ol)liqnc plane of some width, a character whicli is only seen in (lie /. 

 longirostris among the other species of this genus known to me. The exter- 

 nal areas are narrow; tlic posterior quite small. Tin; anterior is elongate, and 

 extends far in advance of the inner areas along the summit of a horizontal 

 ridge, which is produced as a strong step of the outer margin. The outer 



