KANSAS UNIVERSITY OUARTERl.W 



as they were. Nevertheless, there can be no (juestion of their dis- 

 tinction, as shown in the more developed zygosi)hene, the shape of 

 the prefrontals, the number of pterygoid teeth, etc. 



Dinotomius atrox, gen. et sp. uov. Miichterudonliiue I'luli- XVIII. 



Among the most valuable acquisitions of the Bad Land E.Kpedition 

 were two skeletons of a large sabre-toothed cat which proves to be 

 new to science. Both skeletons were found on precisely the same 

 horizon and about twenty feet distant from each other, just below the 

 nodular layer which marks the upper limits of the Oreodon beds of 

 Wortman. One of the skeletons, slightly smaller than the other, 

 comprises the nearly complete skull and numerous bones of tlie 

 skeleton. The skull of the other specimen has been weathered out 

 of the matri.x and includes only the posterior part of the cranium 

 and the mandibles with a part of the upper jaw and a canine. 

 Altogether the two specimens include about thirty vertebrie from 

 various parts of the cohunn, a part of one scapula, humeri, ulnai, 

 incomplete radius, four metacarpals, the pelvis, femora, tibire, the 

 ends of the fibula, calcanei, astraguli, cuboids, and one or two 

 carpals. The material, it is thus seen, is sufficient for the nearly 

 complete description of the osteology and restoration of the animal, 

 which will be given in the July number of this Quarterly by Mr. E. S. 

 Riggs and myself. 



Char, gener. Dentition: Ii|, C\, Pm|, M|. Superior canines 

 much elongated anrl recurved, with anterior and posterior denticulated 

 cutting edge. Mandible with a ridge separating the front from the 

 lateral faces, and with a deep flange in front. Alisphenoid canal 

 present. Superior sectorial without deuterocone, and with a small 

 anterior median lobe; inferior sectorial with entoconid and rudiment- 

 ary hypoconid. Entepicondylar foramen present. Femur without 

 third trochanter. 



In the shape of the skull, as well as in other characters, the genus 

 seems to approach AlacJiaerodiis most closely, and it is possible may 

 not be distinguished from it in its wide sense. 



The sagittal and frontal planes make only a slight angle with each 

 other, less than is the case in any other of the older American 

 Machaerodonts which have been figured. In profile, as well as in 

 the appearance of the lower surface, the skull is more like that of 

 Smilodon neogiviis Luntl. from the Pampas of South America, though 

 a difference is seen in the more slender zygoma as well as in the 

 concave sagittal crest. The brain case is small, having not twice the 

 actual capacity of that of the living Canada lynx, while the animal 

 was four-fifths the size of the African lion. The cranium is much 



