660 The American Naturalist. [July, 
Cynodesmus gen. nov.—Dentition like the microdont forms of Canis, 
but with the skull structure of the more ancient genera. Cerebral 
hemispheres small, not overlapping the olfactory lobes or cerebellum, 
with fewer and simpler convolutions than any of the recent Canide. 
Post-glenoid foramen concealed or absent. 
C. thooides sp. nov.—Dentition microdont; deuterocone of ?* rela- 
tively large ; face short and cranium long; small frontal sinuses pres- 
ent; mandible non-lobate ; size medium. 
This genus represents the direct canine ancestor which the John 
Day beds have hitherto failed to yield. Found by | O. C. "Ru in 
the lower strata. 
? Canis anceps sp. nov.—A fragment of mandible containing pı, mi 
m2 agrees well with C. brachypus Cope, except for its smaller size id 
moreslender jaw. The lower sectorial is nearly as long as in that spe- 
cies (as 17 : 19), but the depth of the mandible is much less (as 21 : 30.) 
The primitive character of the sectorial renders the generie reference 
uncertain. Upper beds. 
Steneofiber montanus sp. nov.—This species is most like the S. ( Castor) 
peninsulatus Cope from the John Day of Oregon, but the upper molars 
(except ™) have but two fossettes, both of which are anterior to the 
enamel inflection. In the lower molars the antero-posterior diameter 
of the crown exceeds the transverse. Found by C. C. Jefferson in the 
lower beds. 
The name Anchitherium has been much too extensively applied to 
American equines. The following table will show the generic distinc- 
tions in the Miocene forms of this group which appear to be justified 
by present knowledge. 
I. Teeth brachyodont. 
A. Conules of upper cheek teeth well-marked; posterior transverse 
crest not reaching the outer wall; external cusps moderately con- 
cave or flattened; anterior pillar of lower teeth distinctly marked. 
1. No cement present. 
a. Incisors without enamel pits Mesohippus Marsh. 
b. Upper incisors with enamel pits. Miohippus Marsh. 
2. Cement on cheek teeth. 
Posterior transverse crests of upper teeth confluent with the external 
wall. Desmatippus gen. nov. 
