Freiburger historische Bestände - digital

EXPLANATION

OF

PLATE 28.

Fig. 1. Right half of the skull g, on which the palatine bone has been removed and parts of the basi-
sphenoid and of the presphenoid have been cut away, so that the whole of that part of the maxillary bone, in
which the still quite unworn m2 is enclosed, is exposed from the medial side. It is a thinwalled bony vesicle,
parts of the bony wall having been replaced by membranes of connective tissue (the holes in the figure, in
one. of which a little of the tooth-plates is seen). Remarkable is the very oblique direction of the tooth, that
part of it which should afterwards have been the grinding surface being placed in such a manner that it forms
an angle of about 100° with the grinding surface of the tooth in action (mx).

Fig. 2. The same skull seen from behind and somewhat from the under side. Most of the long series of
lamellae of m2 are seen; only a few anterior lamellae are connected. The tooth m1 is seen in excessive shortening.

Fig. 3. The skull of the Elephant c from the left side. The thin bony wall which covers the pneumatic
rooms has been cut away, only a few stripes having been left. Also the lateral wall of the teeth has been cut
away. The os jugale has been removed. About J nat. size.

Fig. 4. Skull of the Elephant h treated in the same wise. About f nat. size.

The extreme multiplying of the compartments of the air-sinuses due to increasing age is well seen in comparing
these two skulls.

Comp. for the figs. 3—4 the schematic figures PI. 43 fig. 2 and PI. 44 fig. 1.