MOTION. 



45S 



articulations of the carpal and tarsal bones 

 allow a very limited motion. The axes of these 

 bones are inclined almost vertically, but those 

 of the metatarsal and metacarpal bones are 

 directed rather more horizontally. The phalan- 

 ges of the toes diverge from each other to give 

 a broader base of support to these great digiti- 

 grade quadrupeds: their walk is slow and heavy, 

 and the order in which the legs move is the 

 same as in the Solidungula. 



Carnivora. In the structure of carnivorous 

 quadrupeds, such as the Lion and Tiger, we 

 observe the strength of the more ponderous 

 and slow-moving Ruminants, as the Ox, com- 

 bined with the agility and speed of those 

 lighter forms, as the Stag. This union of 

 strength with speed is due to the geometrical 

 and physical relations of the elements that enter 

 into the composition of these powerful digiti- 

 grade Carnivora. The spine possesses greater 

 mobility by the retraction of the spinous and 

 transverse processes, and the trunk is of less 

 weight and bulk compared to their mus- 

 cular power than in the herbivorous rumi 

 nants. In the Lion the scapula, which is 

 directed very obliquely forwards, is unfettered 

 in its motions by a clavicle ; the humerus is 

 long and cylindrical, and has its axis directed 

 downwards and backwards, forming, with that 

 of the scapula, an angle of 110; the radius 

 and ulna are articulated so as to allow of pro- 

 nation and supination ; the olecranon projects 

 several inches beyond the axis of rotation in 

 the elbow-joint, and constitutes a powerful 

 lever for the application of the tendons of the 

 extensor muscles of the arm ; the direction of 

 the sacro-iliac articulation is eccentric to that of 

 the sacrum, and the pelvis, which is inclined 

 very obliquely backwards, forms, with the pro- 

 jection of the vertebral column, an angle of 

 about 110; the femur is directed forwards in 

 standing at an angle with the pelvis of 84; the 

 tibia and fibula are distinct bones ; the calca- 

 neum is of great length ; the tarsus and meta- 

 tarsus inclined vertically, the phalanges horizon- 

 tally; the last of which is elevated above the 

 plane of motion.* In both the arms and legs 

 the phalanges terminate in strong, curved, re- 

 tractile claws for the prehension and laceration 

 of prey. The posterior extremities in both the 

 lion and tiger are longer, and the bones in- 

 clined more obliquely to each other than the 

 anterior, giving them greater elasticity and 

 power in springing : they walk, trot, and 

 gallop upon the same principle as the horse. 



Cheiroptera.' The bat being principally or- 

 ganized for flight, is provided with compara- 

 tively diminished powers of progression upon 

 solids ; the legs are feeble and incapable of 

 supporting the trunk, and they move by 

 a crawling, and sometimes a small leaping 

 motion. 



Quadrumanu. Of all Mammalia, the figure 

 and organization of the Quadrumana approx- 

 imates most nearly to man. They are destined 



* It is in consequence of the direction which the 

 tarsal, metatarsal, aud phalangeal bones take, 

 that the Carnivora and other animals arc digiti- 

 grade. 



to climb the trees of the forest; to leap from 

 branch to branch ; to walk, trot, or gallop as 

 quadrupeds upon plain surfaces, with the trunk 

 directed either horizontally, or to walk as 

 bipeds upon the posterior extremities alone, 

 with the trunk directed vertically. For these 

 several positions of the trunk and modes of 

 progression they are furnished with a suitable 

 geometrical conformation of their osseous frame- 

 work, more especially in the Ourangs and 

 Chimpanzee. In the Quadrumana the spinal 

 column has greater freedom of motion than in 

 the Pachydermata and Ruminantia. The sca- 

 pula, which is directed forwards at an acute 

 angle with the vertebral column, is supported 

 by a clavicle ; the ginglymoid cavity is deep, for 

 the secure rotation of the head of the humerus ; 

 the latter is long, but slender in the Hylobates 

 or long-armed Gibbon ; the radius and ulna 

 are distinct and free from the motions of pro- 

 nation and supination ; the carpus is often 

 composed of nine bones by the division of one 

 in the second row, to give greater mobility to 

 the hand; the metacarpus and phalanges are 

 much lengthened, but the same in number as 

 in man ; the iliac bones, which are long and 

 narrow, are directed backwards nearly parallel 

 to the vertebral column, but presenting with it 

 posteriorly a very small angle ; the tuberosities 

 of the ischium incline outwards, giving a large 

 base of support to the animal when resting on its 

 callosities. In the Hylobates, the femur is curved 

 and of less length than the humerus, but it is 

 nearly of equal length in the Chimpanzee and 

 Ourangs. The tibia and fibula are long and slen- 

 der ; the articulations of the astragalus, calcis, 

 scaphoid, cuboid, and cuneiform bones are 

 directed obliquely, which gives to the ankle- 

 joint a motion eccentric to the axis of the leg, 

 the effect of which is to throw the animal upon 

 the outer edge of the hands and feet. The 

 long metatarsal and phalangeal bones are in- 

 clined upwards and inwards, by which they are 

 adapted for prehension in climbing or standing 

 on the branches of trees ; the calcaneum is 

 short, and its axis of motion is eccentric, 

 with respect to the direction of the tendons of 

 the gastrocnemius and soleus muscles ; which, 

 though not very powerful, act at a mechanical 

 disadvantage tending lo diminish their effective 

 force in a twofold manner. In many Quadru- 

 mana, as the Cercopithecus and Semno- 

 pithecus, the lengthened and flexible tail is 

 employed as an organ of prehension, but in 

 the Macacus and others the tail is pendent, 

 and not employed in their movements. In the 

 Mandrills the tail is very short; the Simia, 

 Pithecus and Simia Innuus have merely a tuber- 

 cle, whilst the Ourangs and Gibbons are desti- 

 tute of this organ altogether; the deficiency of 

 the mass of extensor muscles of the ankle- 

 joint in the Gibbons and Jockos is alleged by 

 Daubenton* as a reason why these apes cannot 

 maintain themselves in the erect position. Per- 

 rault is of opinion that the straightness of 

 the ossa ilia prevents the extensor muscles 



* Encyclop. Methodique Dictionnaire des Axxi- 

 maux, p. 20. 



