becomes condensed into a pair of cords which receive accessions from the cervical spines, by which the ligaments seem bound down so as to follow the curve of the neck: the insertions are into the superoccipital. Posteriorly a continuation of the ligament may be traced spreading out and losing itself in the base of the single hump of the Dromedary, and as far back as that of the hind hump in the Camel.1

The relative size and insertions (a cervical, b nuchal) of the ligamentum nucha of the Elephant are shown in fig. 22. Much of the same kind of yellow elastic tissue is combined with the aponeuroses of the abdominal muscles in the Elephant, Rhinoceros, and Giraffe, in reference to the capacity and heavy contents of parts of the alimentary canal.

22

Ligamentum nuchæ, Elephant.

§ 199. Muscles of Carnivora.-The commencement of certain facial muscles that reach their full developement in Man may be discerned in the Unguiculates. Small detached sheets of muscular fibre,' cervico-facial' or 'platysma inyoïdes,' are attached to the skin at the side of the neck, spread upon the lateral integuments of the face, and, in the Cat, show a special arrangement or developement by affording a muscular capsule to the bulb of each long hair of the whiskers, upon the chin, lips, cheeks, and eyebrows, to which they give the impressive movements of those sensitive parts. Both the occipital' and 'frontal' parts of the human occipito-frontalis' are also present in the Cat

The muscles of the jaws in Carnivora are chiefly remarkable for the large proportional size of the temporalis,' with which the masseter,' by the more vertical disposition of its fibres than in Herbivora, combines in the act of forcibly closing the mouth. The 'pterygoidei' are small and not very distinct from each 2 V. p. 36.

VOL. III.

I VI.

E

other. The digastric' is a powerful muscle and seemingly 'monogastric,' but many tendinous filaments in the middle of the carneous substance indicate the division which is established in higher Gyrencephala. In the Lion it arises by a strong tendon from the paroccipital; and its action may be seen in the effort the animal makes to disengage the mandible from ligamentous parts of its food. In the Felines the latissimus dorsi has its chief insertion into the tendinous arch, bridging over the biceps, and, with the dermo-humeralis' similarly inserted, it acts upon the inner side of the upper part of the humerus, but sends a strong aponeurosis between the external and scapular heads' or portions of the triceps to be continued upon the antibrachial fascia : in the Dog, a distinct fasciculus of the muscle combines its tendon with that of the scapular' portion of the triceps. In the Sealtribe the retractile action of the latissimus dorsi is extended, by the aponeurotic insertion, to the palmar aspect of the pectoral fin. The homologue of the serratus posticus superior' is largely developed in the Lion, extending its anterior attachments to the nape. The protractor scapula' arises in Felines from the diapophyses of the atlas, axis, and third cervical, and is inserted into the spine of the scapula near the acromion. The origins of thegreat pectoral muscles' interblend and cross each other in Felines, so as to seem to form a common adductor muscle of the fore-limbs; but the mass of the fibres resolves itself into four almost distinct muscles, answering to the large pectoral' and grand pectoral of Hippotomists, and including the sternotrachiterien' and 'pectoantébrachial' of Straus-Durckheim. The pectoralis minor' in the Dog is inserted into the upper part of the glenoid cavity of the scapula. In unguiculate, and especially claviculate, Gyrencephala, the deltoid conforms by the greater extent of origin and size to the more varied movements of the humerus, as compared with the ungulate order. In the Cat the deltoid consists of an anterior portion arising from the acromion, and a posterior one from the spine, of the scapula: in the Bear only the acromial portion is developed. In nonclaviculate Carnivora the masto-humeralis' is present: in claviculate species the cleido-cucullaris' and 'cleido-mastoideus' are its divisions: the former, in Felines, rises from the paroccipital crest, and from the neural spines of the anterior cervicals, passes back and down to the transverse ligamentous tract in which the clavicular ossicle is developed; the cleido-mastoid' is inserted into two outer thirds of the clavicular bone, whence is continued a fleshy belly descending along the fore-part of the brachium, in

front of the biceps, to be inserted into the tuberosity of the radius: it answers to 8, fig. 18, in Ungulates. The biceps, in Felines, derives its single head from the upper rim of the glenoid cavity, and is inserted into the bicipital tuberosity of the radius. The brachialis internus' is a long muscle on the outer side of the humerus, and is inserted into the lower wall of the sigmoid cavity of the ulna. The triceps extensor' is represented by three or more muscles, distinct in their fleshy part, and remarkable for their volume in Felines: their common tendon incloses the olecranon like a strong capsule. Besides the foregoing there are three shorter extensors, one of which is represented by the human anconeus;' but all belong to the same system as the tricipital extensor. The pronator teres' is proportionally large: in the Lion its carneous part extends far down the fore-arm: in the Cat it ends in the tendon inserted about half way down the radius. The palmaris longus' is also more developed than in man. The supinator longus,' on the other hand, has a short and slender fleshy portion; and this relates to the habitual prone position of the paw in Carnivora. The flexors and extensors of the carpus and manus closely accord with those of Man, but with excess of fleshy fibres in the larger Felines; and a minor degree of distinction of some muscles, as, e. g., the 'flexores digitorum,' and 'extensores pollicis.' The extensor longus pollicis' has its origin from the outer wall of the sigmoid cavity of the ulna and the upper third of that bone: its long and slender tendon is inserted into the first phalanx of the pollex, but usually, also, into that of the index. By this insertion, as well as by its high origin, it is less differentiated from the common extensor digitorum' than in Man. There is no extensor brevis pollicis.' The indicator' is represented, in Felines, by a short and slender muscle from the lower half of the outer side of the ulna: its tendon glides through the same carpal synovial sheath as that of the extensor longus pollicis: it has not a separate insertion into the index, but blends with the tendinous division of the common extensor going to that digit. The differentiation establishing the muscle as a true or independent indicator' has not yet come about.

6

The flexor sublimis' is a powerful muscle and the principal bender of the paw in ordinary locomotion; its origin is restricted to the humerus; its insertions are extended into all the five digits by the fascia attached to the sides of the metacarpo-phalangial joints, as well as the ordinary perforated tendons into the sides of the first and second phalanges. The flexor profundus' arises by five heads from the antibrachium, which form a common flattened

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. In cach 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.

6

§ 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.

6

From the Aye-aye to the Gorilla,' with a few exceptions, there is a cleidomastoideus' as well as a sterno-cleido-mastoideus; ' but 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 tendinous 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 c. p. 30, pl. xi, fig. 1, 22 d. 2 cır. p. 34, pl. xi. fig. 4, e.