M A C II A III D U S OF NEBRASKA. 565 



inch in its length and absohitely very much more robust and stronger than in 

 species of Fehs of larger size. 



The passage to the meatus auditorius externus between the post-glenoid tubercle 

 and the mastoid process is relatively very much narrower than in the Panther. 



The face is more uniform in breadth along the course of the nose than in the 

 Panther, and is convex and not depressed as in the latter, above the infra-orbitar 

 foramina. 



The forehead is elevated one inch above the extremity of the post-orbitar pro- 

 cesses, is transversely very convex, depressed along the median line, and presents 

 very obliquely forward. 



The malar bones are relatively narrow ; the face below their anterior extremity 

 relatively broad. 



The infra-orbitar foramina are twice the size of those of the Panther. The orbits 

 present in about the same direction as in the latter. The squamous, coronal, 

 interparietal, and interfrontal sutures are obliterated. The fronto-maxillary and 

 naso-frontal sutures are strongly serrated. 



The intermaxillary bone reaches to within a half inch of the frontal. 



In the lower jaw a striking character is the relatively short coronoid process 

 which is also vertical, or not at all curved backward. The post-coronoid process 

 bends outward instead of inward, as in the species of Felis. About three inches from 

 the condyle, near the base, and proceeding to it, is a ridge, apparently the com- 

 mencement of the inferior margin of the remarkable alar process of the chin of 

 Machairodus. 



Dentition. — The superior canines, judging from their much mutilated stumps, 

 have been very long, compressed in form, but relatively narrow antero-posteriorly 

 to those of Machairodus neogaaus. At their alveoli they measure seven lines 

 antero-posteriorly, and four lines transversely. The concave border of one of the 

 teeth in the fossil, nine lines below the base of the enamel, commences to be tren- 

 chant, and delicately serrulated. Also, antero-internalty, the oblique serrulated 

 ridge begins at the base of the crown, and is directed anteriorly. 



The superior incisive alveoli remain in the specimen : they are of very large size, 

 and increase from the first at the median line to the last, and leave no interval or 

 hiatus between the latter and the superior canine for the reception of the lower 

 canine. 



The hiatus between the superior canine and the second molar, the first liavin.o- 

 been shed, as if depending upon the diminished breadth of the former, compared 

 to its condition in Machairodus neogasus, is unusually large, being seven lines. 



The second molar relative to that of the Panther, is small ; it is also short in 

 relation to its breadth. It has three distinct lobes : an anterior, oblong talon, a 

 posterior, simple, compressed, trenchant lobe, separated by a notch from a middle, 

 compressed, conoidal cusp. 



The superior carnassial tooth presents the same form as in Machairodus neogseus, 

 and is particularly distinguishable from that of the true Cats by its middle lobe 

 being broad and trenchant instead of pointed. 



In the lower jaw, as before mentioned, the chin is broken away, but upon one 



