762 The American Naturalist. [September, 
nent, being a horizontal ledge extension of the inferior face of the 
ramus, which rises gradually to the internal extremity of the condyle. 
The condyle is unusually extended transversely for the size of the 
ramus; the extension being principally external. The internal inflec- 
tion commences below the posterior base of the coronoid process and 
its border extends diagonally inwards and anteriorly. It bounds a 
large dental foramen and canal. 
Measurements. mm. 
Length of ramus from canine alveolus to and _— condyle 75 
Length from last true molar to and including condy] 37 
Length of inferior premolar series 17 
Diameters of last premolar ating kee 6 
Diameters of true molar Í iearionhai pied 
Depth of ramus at premolar 1.... 15 
Depth of ramus at molar 3 16 
Transverse diameter of Sandee 16 
Diameters superior premolar 1 f transverse : 
t EE Seger E A 7 
Anteroposterior diameter true molar 5 
The jaws are about the size of those 5 the gray fox, Vulpes cinereo- 
argentatus. 
Prof. Marsh (Amer. Jour. Sci. Arts, March, 1892, p. 251) regards 
the fauna of the Laramie as widely different from that of the Puerco, 
which succeeded it. He says “the more the two are compared the 
stronger becomes the contrast between them.” Itis true that no Ungu- 
lata have been yet found in the Laramie, while they abound in the 
Puerco, but we cannot be sure that they will not yet be found; the 
probabilities are that they existed during the Laramie, and that it is 
due to accident that they have not been obtained. But the’ Multitu- 
berculata of the two faunæ are much alike. Thus the Dipriodon luna- 
tus (Marsh 1. c., Pl. v, fig. 7,) appears to be a species of Ptilodus Cope, 
and the Cimolodon nitidus (l. c. vi, fig. 9,) is either a species of that 
genus or of Neoplagiaulax Lem., both genera characteristic of the 
erco 
EXPLANATION OF PLATE. 
` All the figures natural size. 
Fig. 1. Fragment of maxillary bone external view: 1 a internal 
view; 1 5 Siferiox view. 
Fig. 2. Left mandibular ramus external view: 2 a internal view; 
2 b superior view.—E. D. Corr. 
