Page 17 - maxson1928

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!.C. intermontanus M. intermonte.nus M.c.stylodontus
(Mint Canyon)

Antero-poster:Lor diameter ----- a~10 --------- i3.4 -------- 23.4

fJ.ransverse II ------ a25 -------- 24.8 ------- 23.8
1
Height ------- - ------------ 29 -------

P- No. 30041 u.c.
2
Antero-posterior diameter 21. ~'J ------- 21.2 ------- al8.5

Transverse fl ------- 15.0 -------

P- No. 30041 u.c.
3
Antero-posterior diameter ------ 21.0 -------- 20.4 18.9

'1ransverse ft 17.0 ------- 14.2
1

It would appear possible on the basis of size and agreement of

characters noted ia the dentition to assign the Mint Canyon form to the

species Merychippus intermontanus. '11he similarity of this Great Basim

form to the Great Plains species M. sejunctus and Protohippus perditus

is quite interesting. Matthew (1915) regards the former as pointing

toward the latter type. M. intermontanus from the Barstow and also the

slightly larger form from the Mint Canyon may be associated with the

protohippine stem in which case it is possible that they descended from a

form similar tQ :M. sejunctus. The Mint Canyon ;,:::erychippus intermontanus

appproaches very closely the genus Protohippus and possibly should be

referred to it.

PROTOHIPPUS?, sp.

A fourth distinct type of equine yielded by the Mint Canyon

series is represented by three and possibly four lower cheek teeth (No.30041

U.C.). The specimens are apparently worn and considerably weathered. The

teeth are definitel;r hypaodont and the crowns are heavily cemented. See

Plate I. Fig. 6.