1, Outline of the thorax at the level of the third dorsal vertebra; 2, 2, scapula; 3, spinal border of the scapula; 4, contour of the skin.

In quadrupeds whose scapula, on the contrary, is wanting in the cartilage of prolongation (in the clawed,[7] such as the cat and dog), the superior border of the scapula is visible, especially when the animal is resting on its fore-limbs, particularly when it crouches; at such a time the skin is markedly raised by that border; and the spinous processes of the vertebræ, beyond which it projects, occupy the bottom of a fossa ([Fig. 15]). The internal surface of the scapula is turned towards the ribs; it is known, as in man (in whom this surface is anterior), as the subscapular fossa.

[7] For the definition of this word, see [p. 37].

Fig. 16.—Left Clavicle of the Cat: Superior Surface (Natural Size).

1, Internal extremity; 2, external extremity.

Fig. 17.—Clavicle of the Dog (Natural Size).