. Cassell's natural history. Animals; Animal behavior. 110 NATURAL HISTORY. by a modification of a imiscle, which in man and the Cliimpanzee, for instance, stretches from the toj) of the bhulebone, across the lower part of the neck, to the bone at the base of the tongiie (tlie oino-hyoid muscle). It has also two bellies in man, or, in other words, the muscular fibres are attached to the bladebone and to the hyoid bone, and there is an intermediate tendon ; moreover, this passes tlu-ough a pulley, so that the obliquely-iilaced muscle in the lower part of the neck acts straight upon the tongue,
. Cassell's natural history. Animals; Animal behavior. 110 NATURAL HISTORY. by a modification of a imiscle, which in man and the Cliimpanzee, for instance, stretches from the toj) of the bhulebone, across the lower part of the neck, to the bone at the base of the tongiie (tlie oino-hyoid muscle). It has also two bellies in man, or, in other words, the muscular fibres are attached to the bladebone and to the hyoid bone, and there is an intermediate tendon ; moreover, this passes tlu-ough a pulley, so that the obliquely-iilaced muscle in the lower part of the neck acts straight upon the tongue, and pulls it down in a right line. In the Macaques, this muscle has no central tendon, and the muscular fibres jiass all the distance from the bladebone to the os hyoides at tlie base of the tongue. • ' In addition to these modifications where muscle replaces tendon, there are those of several other muscles which act on the tongue, the larynx, and on the upper and lower parts of the windpipe, their. conjoined action being to approximate all these parts. These muscles, which are separate in man, are united in one in the Macaques. The head of these Monkeys, hanging as it does when they go on all-fours, requires extra supjiort, and one of the muscles of the back, which from its square shape is called the rhomb-shaped muscle, is especially attached to the occiput, and helps to hold the head up. Another assistant in the move- ment on all-fours is a muscle which pulls the bladebone forwards when the animal is walking. It springs from the outer processes of the upper bones of the neck (transverse process of the upper cervical vertebra}), and is attached to the spine of the bladebone. This muscle is seen in the great beasts of prey also, and in the Semnopitheci and Guenons. A similar " wild-beast" peculiarity exists in the an-angement of the muscles of the hand; the muscle which extends the little finger and opens it is divided, and has greater connections with the fourth f
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