332 SYNOPSIS or the vertebrate fauna of the puerco series. 



Measurements. M. 



[ long, with great tuberosity 021 



Diameters of Iiead of humerus i , , ,, „ ., ^r, 



(^ short, " small " fli 



Least diameter of sliaft do OOo 



Width of distal end do 035 



" " condyles in front 015 



f transverse 0105 



Diameters distal end of radius J. . .„„ 



I vertical ouy 



Ilium anterior widtli of peduncle 010 



" external " " " Ol'l 



This species is one of medium size in the j^enus. It is quite of the type of the 

 M.ferox and M. corrugatus. Its inferior molar teeth are considerably larger than 

 those of the M. prolog onioides, and the last one is shorter in relation to its length. 

 It is dedicated to Professor W. H, Flower, Director of the Natural History Depart- 

 ment of the British Museum. 



MiocL^NOS CORUUGATUS Cope ; Proc. Amer. Phil. Soc, 1883, p. 560; Tertiary Mammalia, 1885, p. 341, PL XXIV f, 

 fig. 5 ; XXIV g, fig. 8. 



The discovery of nearly entire mandibular rami of this species and of M.ferox 

 enables me to determine the distinctive characters of the two species better than 

 heretofore. While the true molar teeth in the two are of nearly equal size, or at least 

 within the range of variation not unusual in a variable species, the mandibular ramus 

 of the M. corrugatus is very much smaller every way than that of the M. ferox. 

 The shortening influences the length of the premolar series, which is much shorter 

 in the M. corrugatus, the teeth being crowded, while in the M.ferox they are (the sec- 

 ond, third and fourth) separated by interspaces. An astragalus which accompanies 

 the jaws of 3£ corrugatus is identical in character with that of the M. ferox but of 

 smaller size. 



MiocLJENUs OPisTiiAcns Cope ; Amer. Naturalist, 1883, p. 833. Hemiihlmus opisihaeus Cope ; Tertiary Vertebrata, 

 p. 407, PI. XXV f, figs. 8-9. 



The typical specimens of this species include parts of four mandibular rami with 

 teeth, and a single superior molar, which is that of a species of Hemithljeus. The 

 association of this superior molar with the mandibles cannot be demonstrated. I 

 have subsequently received a mandibular ramus with nearly complete dental series, 

 associated with a portion of a skull which contains the true molars and the first pre- 

 molar in a perfect state of [)reservation. Everything inspires the belief that these 

 are parts of the same animal. In addition I have parts of both rami of a sixth indi- 

 vidual which support most of the teeth ; and a maxillary bone with m. ii, m. i and p. 

 m. i, with parts of mandibles of a seventh, and mandibles of five other individuals. 



