In

tendon, along the carpus; this first detaches a tendon to the ungual phalanx of the pollex, and, at the metacarpus, divides into the four tendons similarly inserted into the four long digits. each the insertion, fig. 36, b, is into the lever-like process from the palmar part of the bone of the last phalanx. It is this muscle which overcomes the retractile force of the elastic ligaments, ib. a, of the claws, and concentrates the power of all five upon the part seized. There is no separate flexor longus pollicis.'

In the hind limb of Felines, the psoas and iliacus are more obviously parts of the same muscle than in Man: a fasciculus of the psoas' sends a tendon to the pubis; but the main body of the muscle acts upon the inner trochanter. In the Cat a detachment of the small ectogluteus descends to be inserted into the patella. The much longer mesogluteus has five origins from lumbar, sacral and caudal vertebræ, and from the crista ilii: its tendon goes to the great trochanter. The gracilis' is relatively large. The muscle at the foremost part of the thigh, in Felines, answers to the sartorius' and rectus femoris;' there is also a ' tensor fascia,' which sends an aponeurosis over the fore part of the knee-joint and a tendon to the inner part of the head of the tibia. The biceps flexor cruris' receives a slender accessory fascicule from an anterior caudal vertebra; besides its normal insertion it is continued by fascia into the tendo achillis.' In the Lion, a special muscle, caudo-femoralis,' from the same vertebræ is inserted by its own long tendon into the outer condyle of the femur. The Bear has not the latter muscle. The largest part of the 'gastrocnemii' muscles is at or near to their femoral origins : the tendons of each are at first distinct, and finally blend by expansions which spread over the calcaneum. The soleus is small, and rises from the fibula: its tendon unites with that of the gastrocnemius externus. The tendon of the plantaris' combines with that of the short flexor' of the toes to augment the power of bending their phalanges: its fleshy part is relatively much greater than in Man.

$ 200. Muscles of Quadrumana.-In this series, up to the apes, the panniculus carnosus exists; but is reduced to a thin sheet of carneous fibres from the dorso-lumbar fascia, spreading over the latissimus dorsi, and again degenerating to fascia attached to the inner side of the humerus. The platysma myoïdes' begins to be defined, in the Aye-aye, as a pair of broad thin layers, arising from pectoral and clavicular fascia, and ascending over the front and sides of the neck, mandibular rami, and cheeks. In the Orangs and Chimpanzees it supports the large cervico-pectoral air-sac communicating with the larynx.

From the Aye-aye to the Gorilla,' with a few exceptions, there is a cleido-mastoideus' as well as a sterno-cleido-mastoideus; bat in some Baboons (Macacus) the distinct fasciculus from the clavicle has not been found. In an Orang I found the cleidal part inserted into the diapophysis of the axis vertebra.

The term ' digastricus' is applicable to that mandibular muscle in all Quadrumana, although the partition by tendon of the anterior from the posterior belly is not complete in many. In most, as in the Aye-aye, the anterior portions of the pair occupy the Anterior interspace of the mandibular rami. The middle tendiDous part is attached to the hyoid, except where it is feebly marked, as in Stenops. The intermediate tendon of the omohyoid is not found save in the higher tail-less Apes.

In all Quadrumana the power of the arms in drawing up the trunk is increased by the accessory muscle from the ordinary tendon of the latissimus dorsi,' which extends its action from the upper to the lower end of the humerus (interior condyle), and to the olecranon. The rhomboidei' extend to the occiput in Macaques, Baboons, and the Orang. The 'protractor scapula' ('acromio-trachelien,' Cuv.) exists in most Quadrumana below the Apes; in these the 'levator anguli scapula' is distinct from the 'serratus magnus; but is the fore part of that muscle in Baboons.' In the Gibbons (Hylobates) the two portions of the 'biceps flexor cubiti' are more powerful and unite lower down the lumerus than in other Quadrumana, and the inner portion derives an origin from near the pectoral ridge of the humerus: their common tendon is inserted beneath the radial tubercle, and into the antibrachial fascia. In Stenops the biceps has only its 'long head' or origin: that from the coracoid process is, at least, not distinct from the coraco-brachialis. The triceps extensor cubiti' is complicated in Quadrumana by the accessory fasciculus in connection with the tendon of the latissimus dorsi. The lower portion of the internal head' of the triceps has also a distinct origin or fasciculus from the entoCondyloid ridge in Chiromys and Tarsius; in Stenops it arises more from the back part of the humerus.

The deep and superficial flexors of the fingers are distinct, but a remnant of that blending which exists in most lower mammals may be seen in the short connecting tendon which in the Aye-aye2 passes from the ulnar belly of the flexor sublimis' to the division of the 'flexor profundus,' giving off the tendon to the middle finger. The fleshy part of both flexors, but especially of the deeper one, is continued nearer to the hand, in Lemuride and most other

1

c. p. 30, pl. xi, fig. 1, 22 d.

2

CII'.

I. p. 34, pl. xi. fig. 4, e.

Quadrumana, than in Man, thus enabling the muscles to continue their action as finger-benders when the hand itself is flexed. The fasciculus of the flexor profundus' which sends the tendon to the last phalanx of the thumb, is more distinctly a 'flexor longus pollicis' in Apes than in lower Quadrumana. In the Aye-aye it adheres to the supplementary carpal and fascia on its way to the thumb, and thus opposes both the last phalanx and the 'pad' at the base of the thumb in the act of grasping. The 'flexor brevis,' the abductor,' the adductor,' and 'opponens pollicis' are present in the Chimpanzee and Gorilla, as are likewise the extensor longus' and 'extensor brevis.' In the Orang these muscles begin to be confounded; in most lower Quadrumana they are blended together. The homologue of the 'extensor indicis' of Man bifurcates and sends a tendon to both the index and medius digits; the homologue of the extensor minimi digiti likewise splits and sends a tendon also to the annularis; so that, while in Man the index and minimus only have two extensor tendons, all four fingers (iv) have them in most Quadrumana. The hand is thereby the stronger as a suspensor of the body from a bough.

6

The 'ectogluteus' is feebly developed compared with that in Man: the Gorilla, though receding far in this respect, recedes the least. The homologue of the gracilis' is relatively larger in all Quadrumana than in Man, and its insertion is extended lower down the leg. In Stenops the vastus externus contributes a fasciculus to the rectus femoris; in Chiromys it is as distinct as in higher Quadrumana. But here the mesogluteus exceeds the ectogluteus in size, although the latter is supplemented in the Gorilla by fleshy fasciculi from the ischial tuberosity, which spread their insertions from that of the ectogluteus down the femur to the internal condyle, apparently representing the adductor magnus. In both Orang and Chimpanzee a muscle from the outer border of the ilium to near the acetabulum is inserted into the under and outer part of the great trochanter and rotates the thigh inwards." The gastrocnemii have a greater length and minor breadth and thickness of the fleshy part: the soleus rises from the fibula exclusively, and joins the gastrocnemii low down.

$201. Muscles of Bimana.-The myologies of Anthropotomy reduce the need of noticing human muscles here to some comparison with those of highest Apes, bringing out the ordinal characteristics of the limbs, and to the illustration of those giving expression to the face and reflecting the action of the organ that marks Man's place in Creation as the type of a distinct sub-class. 16 Scansorius,' Trail, xxxv. Invertor femoris,' xxxIV". p. 68.

23

Figures 23 and 24 give a view of the superficial muscles and tendons of the fore-arm and hand of a full-grown male Gorilla and Man of correct relative size. The portion of the triceps is seen in the Gorilla at 2"; in Man at 5', in whom the origins of the carneous fibres of that part from behind the inter-muscular septum are continued lower down the humerus. The brachialis anticus' is seen at 4, fig. 23, and 17, fig. 24. This muscle is not so completely differentiated from the deltoid and supinator longus in the Gorilla as in Man, nor so individualised as a single muscle: its two portions being more distinct. The biceps, fig. 23, 3, maintains in Man more of its full fleshy character to the sending off of the tendon, s', to the rough posterior margin of the tuberosity of the radius, gliding over the anterior smooth surface of that process with an intervening bursa.' The aponeurosis, s", sent off to the fascia of the fore-arm crosses the pronator teres.' This muscle, 8, fig. 24, is attached to the outer side of the radius below the middle of the bone in the Gorilla, but rather above it in Man. The double origin, viz. from the inner humeral condyle and the coronoid process of the ulna, is better defined in Man, fig. 23, 6. The palmaris longus,' fig. 23, 8, arising as a distinct muscle in Man from the inner humeral condyle, is a fasciculus, 5, of the flexor carpi ulnaris' (3, fig. 24) in the Gorilla; but, as this muscle is subject to variation, and sometimes absent in Man, it may show analogous inconstancy in the Gorilla. The flexor carpi ulnaris is inserted into

6

the pisiforme in both Man and Ape, but the Muscles of the fore-arm and hand, fleshy and tendinous parts are better defined,

Man.

and the latter relatively longer and more slender in Man, fig. 23, 9. The flexor carpi radialis arises in Man, fig. 23, 7, from the inner condyle, from the antibrachial fascia and septa continued therefrom between the pronator teres, 6, and palmaris longus, 8; but in the Gorilla, fig. 24, 4, it derives a considerable accession of

fibres directly from the radius, and its tendon is shorter and much :

thicker than in Man. In both it passes through a pulley provided by the trapezium to its insertion into the base of the metacarpal of the index. The tendon of the supinator longus in the Gorilla, fig. 24, 4', is also shorter and thicker, and is not crossed, as in Man, by the extensors of the metacarpal and first phalanx of the pollex (fig. 23, 11 and 12) before its insertion into the styloid process of the radius. Part of the carneous mass of the flexor sublimis digitorum is seen at 13, fig. 23, and 6', fig. 24. External to this a greater proportion of the flexor profundus appears in the Gorilla, fig. 24, 6, than in Man, fig. 23, 15. The flexor longus pollicis, fig. 23, 14, expends its force in the Gorilla, fig. 24, 20, upon both the pollex and index, furnishing tendons to the distal phalanx of each, but the largest and most direct being that to the index. There are modifications of minor

importance in the origin of this muscle which tend to give it a