National Institute of Informatics - Digital Silk Road Project
Digital Archive of Toyo Bunko Rare Books

Later J. C. Forsyth Major,* Mme. Pavlow,† Nehring,‡ Kowalewski,§ and
Woldrich∥ touched more or less at length upon the relation of the skulls of the
ass and horse. Still later some of the French investigators discussed these very
different and partly contradictory criteria, thus Duges,¶ Monfalet,** and before
all X. Lesbre,†† the veterinary anatomist of Lyons.

I will here state briefly those characteristics on which these authors lay
the most stress:

According to Owen, in the upper series of grinders the degree of oblique attri-
tion of premolar 2 causes its working surface to appear more produced and acute
anteriorly than in less worn and more evenly worn specimens. Besides the general
inferiority of size of teeth, molar 3 is relatively less than in Equus caballus and
is not bilobed behind: the outer channels are more evenly curved or concave;
and as the same character prevails in the inner enamel-wall of the lobes these are
more regularly crescentic in shape. The longitudinal ridge is relatively narrower.
A slight excess of fore-and-aft over transverse diameter of grinding surface is
recognizable in the ass—such excess not being seen in the permanent grinders,
premolar 3 to molar 2, of the horse.

Rütimeyer regards as a constant characteristic for the teeth of the ass, as
compared with the horse, the relatively slight length of the foremost as well as of
the hindmost molar in both the upper and lower jaws. Also he considers the
premolars and molars in the ass to be shorter than in the horse; the foremost
premolar tooth is strikingly short. Rütimeyer declares irrelevant the circum-
stance mentioned by Owen that molar 3 superior is less bilobed in its posterior
circumference than in the horse. He ascribes to the ass, at least in the teeth
of the upper jaw, more oblique enamel plications than occur in the horse, but
he remarks that one can not disregard the fact that all these characteristics, in so
far as they concern construction of the teeth, recur in very old horse teeth; there-
fore, in the earlier stages of abrasion, the teeth of the ass show the characteristics
which correspond to the deeper parts of the tooth lying nearer to the root. In
addition to this is the relatively small extent of the toothless part between pre-
molars and canines, as well as the slight width of the incisor crown. Thus, in
the ass the whole construction is more compact and crowded.