674 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 57. 



MYLOHYUS NASUTUS (Leidy). 



Dicotyles nasutus Leidy Proc. Acad. Nat. Sci., Philadelphia, 1868, p. 230. 



Type. — Anterior portion of a palate containing the canine and 

 anterior two premolars of the right side, one incisor of the left side, 

 and the alveolii for the other incisors and the left canine. 



Locality. — Gibson County, Indiana, discovered in digging a well, 

 at a depth of between 30 and 40 feet. 



Diagnosis. — Canines with strongly marked longitudinal ribs, or 

 striations; upper premolars, p^ and p^ (other cheek-teeth not known), 

 with anteroposterior diameter (according to Leidy's measurements) 

 as great or greater than the transverse diameter; parastyle, meta- 

 conule, and hypostyle appearing as well-defined cuspules ; and " a 

 conspicuous outwardly projecting ridge" above the alveolar border 

 of the upper premolars and in advance of the infraorbital canal. 



Measurements, — Taken from Leidy's table of measurements, given 

 in lines and here translated into millimeters : ^ 



Length of diastema behind canine 62. 5 



Anteroposterior diameter of p' 9.2 



Transverse diameter p' 8.2 



Anteroposterior diameter p* 11.4 



Transverse diameter p' 11.4 



Anteroposterior diameter of c 11. 8 



Transverse diameter of c 7. 1 



Width of palate between the third premolars (estimated from Leidy's 



figure) 24. 



MYLOHYUS PENNSYLVANICUS (Leidy). 



Dicotyles pennsylvanicus Leidy, Ann. Rept. Geol. Surv., Pennsylvania, for 

 1887, published in 1889, pp. 8-12, pi. 2, figs. 3-6. 



Type. — Portions of the upper and lower jaws each carrying the 

 milk dentition and the first true molar of each side. 



Locality. — ^" Hartman's," or " Crystal Hill " cave, about 3 miles 

 west of Stroudsburg and 5 miles from the Delaware Water Gap. 



Diagnosis. — A larger species than 31. nasutus, with apparently a 

 relatively shorter diastema between the canine and the cheek-tooth 

 series, and (according to Leidy) with the absence of the " conspicuous 

 outwardly projecting ridge " on the alveolar border above the pre- 

 molars observed in M. nasutus. 



I refer to the species a fragment of a right lower jaw containing 

 the last two molars (Cat. No. 8162, U.S.N.M. Coll.). These teeth are 

 relatively much narrower than the corresponding ones of M. exortivus 

 described on page 676. The measurements are for mg, anteropos- 

 terior diameter 17.2 mm., transverse diameter 13.7 mm.; for nig, 

 anteroposterior diameter 22.3 mm., transverse diameter 13.5 mm. 



' Journ. Acad. Sci., Philadelphia, ser. 2, vol. 7, 1869, p. 387. 



