588 MUSCLES OF MAN CHAP. the greatest stress is laid in walking. As to muscles, the glutaeus maximus is more developed in Man-the Ape which most nearly approaches him being the Gorilla, in which animal the life is less thoroughly arboreal than in some others. The so-called "scansorius" is only present in Man as an occasional occurrence. FIG. 283.-Skeleton of the left pes of a Chimpanzee. (Dorsal aspect.) as, Astragalus ; cb, cuboid; cl, calcaneum; ec, ectocuneiform; en, endocuneiform; ms, mesocuneiform; nr, navicular; I-V, digits. (From Wiedersheim's Structure of Man.) The rudimentary character of the ear muscles for the movement of the external ear in Man has often been insisted upon, as also their occasional functional activity. But here and elsewhere, so numerous are the abnormalities, that "the gap which usually separates the muscular system of Man from that of the Anthropoids appears to be completely bridged over." These are words of Professor Wiedersheim quoted from Testut, and express a final summary of the matter of muscles in Man and the Apes. XVII RUDIMENTARY VOCAL SACS 589 In his teeth Man differs by the small exaggeration of the FIG. 284. The hard palate, A, of a Caucasian; B, of a Negro; C, of an adult OrangUtan, showing the differences in shape of the bones. The palate of the Negro represents a type transitional between that of the Caucasian and that of the Orang. mx, Maxilla; pl, palatine; p.mx, premaxilla. (From Wiedersheim's Structure of Man.) canines, which hardly, if at all, differ in the two sexes. There is also a complete absence of a diastema. The teeth are also on the whole weaker than in the Anthropoids, though Hylobates is very human in this particular. sn. There is a tendency in Man towards the disappearance of the upper outer incisors, and more markedly still of the wisdom teeth, which appear very late, and are often imperfect. In a large number of cases the tooth does not appear at all. In the larynx there is no great development of the great throat pouches of the Anthropoids. The minute diverticula of that organ, known to human anatomists as the ventricles of Morgagni, alone remain to testify to a former howling apparatus in the ancestors of Man. FIG. 285.-Human Larynx in frontal section. cr, Cricoid cartilage; sn, sinus of Morgagni; t.c, first tracheal cartilage; th, thyroid cartilage. (From Wiedersheim's Structure of Man.) |