236 On the Extinct Dogs of North America, [March, : 
molars! Thus in Megalotis the true molars number 3, and in Icti- 
cyon, at the other end of the series, 3. The genus which adds to 
this reduction a further diminution in the number of premolars, 
Dysodus,” is only known in a domesticated condition. 
The Canidz probably first appeared in the Upper Eocene 
epoch. Cuvier described a Canis parisiensis from the Gypsum of © 
Montmartre, but it is not as yet known whether it belongs to — 
the restricted genus Canis or not. From the Phosphorites of — 
Central France come the Canis filholi Mun. Chal., and Brachyeyon ? 
gaudryi Filhol. The phosphatic deposit in which these species — 
than Oligocene or oldest Miocene; that is below the White 
River formation. aed are most abundant in the a 
fauna everywhere. 
I give the following analysis of the extinct genera found 
North America: 
I, Molar formula a $ i. 
Humeras with epitrochl¢ar foramen. auu. oao cee vice eons 
11. Molar formula ¢ 2. 
a, No anterior lobe of, superior sectorial. 
- B. Humerus with epitrochlear foramen. 
Inferior menei with heel wisai, R weer ces fiver eben eee 
Inferior sectorial with heel basin-shaped....... T E oouwe st 
fB. Humerus without epitrochlear foramen, 
Inferior sectorial with heel basin-shaped.............+++- is cee 
aa, An anterior lobe of superior sectorial. 
Heel of lower sectorial basin-shaped ; no epitrochlear foramen . ...+++++ Æl 
tit. Molar formula $ 3. : 
Heel of inferior sectorial trenchant; premolars lobed posteriorly. ...- Eahyd ' 
Heel of inferior sectorial hédinshaped : ; Superior molars unknown, .-++ To 
v. Molar formula 
Heel x inferior sectorial Meter kipci ; internal cusp present...+--++* 
v. Molar formula 4 4. 
Premolars lobed; first inferior two-rooted a E 
To these genera I refer twenty-five species of the An 
Miocenes. 
1! For the genera of Canidæ, see Proceeds, Pe Nat. Sci, Philada., Jae 
7 See on this genus AMERICAN NATURALIST, 1881, p. 233, and July, t 
