OCR Text |
Show 72 foot is longer and the hand much longer in the Gorilla; but the great difference is caused by the arms, which are very much longer than the spine in the Gorilla, very much shorter than the spine in the Man. The question now arises how are the other Apes related to the Gorilla in these respects-taking the length of the spine, measured in the same way, at 100. In an adult Chimpanzee, the arm is only 96, the leg 9o', the hand 43, the foot 39 -so that the hand and the leg depart more from the hu1nan proportion and the arm less, while the foot is about the same as in the Gorilla. In the Orang, the arms are very much longer than in the Gorilla (122), while the legs arc shorter (88); the foot is longer than the hand (52 and 48), and both are 1nuch longer in proportion to the spine. In the other man-like Apes again, the Gibbons, these proportions are still further altered; the length of the arms being to that of the spinal column as 19 to 11; while the legs arc also a third longer than the spinal column, so as to be longer than in Man, instead of shorter. The hand is half as long as the spinal column, and the foot, shorter than the hand, is about -fr ths of the length of the spinal column. Thus Hylobates is as much longer in the arms than the Gorilla, as the Gorilla is longer in the arms than Man; while, on the other hand, it is as much longer in the legs than the Man, as the Man is longer in the legs than the Gorilla, so that it contains within itself the extremest deviations from the average length of both pairs of limbs (see the F1·ontispiece). The Mandrill presents a middle condition, the arms and legs being nearly equal in length, and both being shorter than the spinal column; while hand and foot have nearly the same proportions to one another and to the spine, as in Man. In the Spider monkey ( Ateles) the leg is longer than the spine, and the arm than the leg ; and, finally, in that remarkable Lemurine form, the Indri, (Lichanotus) the leg is about as long as the spinal column, while the arm is not more than fi of its length ; the hand having rather less and the foot rather more, than one third the length of the spinal column. These examples might be greatly multiplied, but they suffice to show that, in whatever proportion of its limbs the Gorilla differs from Man, the other Apes depart still more widely from the Gorilla and that, consequently, such differences of proportion can have no ordinal value. We may next consider the differences presented by the trunk, consist~ng of the vertebral column, or backbone, and the ribs and pelvis, or bony hip-basin, which are connected with it, in Man and in the Gorilla respectively. In Man, in consequence partly of the disposition of the articular surfaces of the vertebrre, and largely of the elastic tension of some of the fibrous bands, or ligaments, which connect these vertebrre together, the spinal column, as a whole, has an elegant S-like curvature, being convex forwards in the neck, concave in the back, convex in the loins, or lumbar region, and concave again in the sacral region ; an arrangement which gives much elasticity to the whole backbone, and diminishes the jar communicated to the spine, and through it to the head, by locomotion in the erect position. Furthermore, under ordinary circumstances, Man has seven vertebrre in his neck, which are called cervical; twelve succeed these, bearing ribs and forming the upper part of the hack, whence they are termed dorsal; five lie in the loins, bearing no distinct, or free, ribs, and are called lumbar; five, united together into a great bone, excavated in front, solidly wedged in between the hip bones, to form the back of the pelvis, and known by the name of the sacrum, succeed these; and finally~ three or four little more or less moveable bones, so small as to be insignificant, constitute the coccyx or rudimentary tail. In the Gorilla, the vertebral column is similarly divided into cervical, dorsal, lumbar, sacral and coccygeal vertebrre, and the total number of cervical and dorsal vcrtcbrre, taken to- |