386 ANIMAL REMAINS FROM THE EXCAVATIONS AT ANAU. 
Siberia, from the Warwarinskischen ‘‘ Yourts,’”’ on the River Tobol, and with the 
djiggetai (Equus hemionus). We must, therefore, first settle the question whether 
these cranial remains really belong to a horse or to a half-ass, like the dyjiggetai, 
or to a kiang. 
Investigation into the relation of the teeth of the horse to those of the djiggetai 
and ass has been carried out most thoroughly by L. Riitimeyer,* R. Owen,T 
J. C. Forsyth Major,t A. Nehring,§ T. Frank,|| and M. Wilckens.{ 
In consequence of these studies the following distinctive characteristics 
between the Western and the Oriental horse groups and the asses are available. 
ORIENTAL HorsE Group (BROAD-FRONTED HORSES). 
The premolars of the upper and lower jaws have a larger or equally large 
transverse diameter of the grinding surface with the longitudinal diameter. The 
plications of the enamel pattern are here considerably smaller than in western 
horses and the interior pillars of the anterior island appear rounded. 
OccIDENTAL HorsE Group (NARROW-FRONTED HorsEs). 
The premolars are here more drawn out in the length; hence the depth of the 
grinding surface is greater than in the transverse diameter. The enamel plications 
of the islands are considerably more folded, and the ant-external horn of the pos- 
terior island surpasses the post-external horn of the anterior island, projecting 
further outward, even on the molars, on which in oriental horses they stand almost 
even. Inthe same way the stronger plication of the enamel margin on the internal 
lobe causes in the Occidental horse the striking bifurcation of the internal lobule 
and the stronger development of the spur** in the ant-oblique valley. 
ASSES AND HALF-ASSES. 
In the asses and half-asses the longitudinal diameter of the crown is still 
shorter in comparison with the transverse diameter than in the oriental horse, 
the enamel plications are less prominent, and the spur is wholly wanting in the 
ant-oblique valley. 
Tscherskif{ gives a method by which he says the relationship to one of the 
groups mentioned can be expressed in figures. This is the determination of the 
index of projection of the anterior lobule of the interior pillar. If we take the 
distance from the posterior margin of the crown to the next point of the bottom 
*Beitraege z. Kenntniss d. fossilen Pferde u. z. vergleich. Odontographie d. Huftiere ueberhaupt. 
Verh. Nat. Ges. Basel, 1863, p. 538. 
+ Description of the Cavern of Bruniquel. Phil. Trans. 1869, p. 517. 
t Beitraege z. Gesch. d. Fossilen Pferde. Schweiz. paleont. Gesell., 1877. 
§ Fossile Pferde aus deutsch. Diluvial Ablagerungen. Landw. Jahrbuecher, 1844. 
||Beitraege z. Rassenkunde unserer Pferde. Landw. Jahrb., 1875. 
{| Beitraege z. Kentniss des Pferdegebisses. Nova Acta, Leop.-Carol. deutsch. Akad. d. Naturf., 1888, 
P2587. 
**The ‘‘spur” of the German authors is the small enamel fold entering from the ant-oblique valley 
into the ant-oblique lobe (Owen’s terminology). 
TT Ob. ctt., p. 320. 
