60 PROFESSOR OWEN ON THE AYE-AYE. 
shoulder-joint over which it passes, to be inserted into the lesser tuberosity of the 
humerus above the teres major. 
The deltoides (Pls. XXII. & XXIII. figs. 1 & 2,15) has the usual extensive origin from 
the outer part of the clavicle, contiguous to the clavicular part of the pectoralis major, 
and from the acromion to near the beginning of the scapular spine. The fibres converge 
to their insertion into the strong ridge along the middle of the fore part of the upper half 
of the humerus. 
The pectoralis major (Pls. XXII. & XXIII. fig. 1, 17) consists of an upper smaller (172) 
and a lower larger (17) portion. The first derives its origin from the sternal half of the 
clavicle and the manubrium sterni ; its fibres pass transversely outward, overlapping 
the insertion of the second portion, and passing to the lower part of the pectoral ridge 
of the humerus. The larger portion of the pectoralis major arises from the fore and 
lateral part of the body of the sternum, and from the cartilages of the eighth, ninth, and 
tenth ribs. The fibres converge to their insertion into the upper two-thirds of the 
pectoral ridge. 
The pectoralis minor arises from the side of the manubrium, and from the sternal ends 
of the first to the fifth ribs: it is inserted by a broad tendon, spreading over the head of 
the humerus, to be attached to the great tuberosity. 
The biceps brachii (Pls. XXII. & XXilIL. fig. 1, 2) rises by a short and thick tendon (a), 
which soon becomes distinct from the coraco-brachialis, from the coracoid process, and 
by a long flattened and strong tendon (ib. ») from the upper border of the glenoid cavity. 
The two portions of muscle unite about one-third down the humerus, and the muscle 
passes over the fore part of the elbow-joint, becoming tendinous (tb. ¢), to be inserted, as 
usual, below the proximal tubercle of the radius. 
The coraco-brachialis (Pls. XXII. & XXIII. fig. 1, 1s) arises from the whole lower border 
of the coracoid process by a broad tendon, which is closely attached to the capsule 
of the shoulder-joint where it passes over the joint, becomes fleshy near its origin, 
and is inserted along the inner side of the middle third of the shaft of the 
humerus ; the portion (4+) which has its insertion extended to the entocondyloid ridge 
seems to have an almost distinct origin by a larger tendon, from the end of the 
coracoid process. 
The brachialis anticus (ib. fig. 1, =) lies to the outer side of the lower half of 
the coraco-brachialis ; arising from the outer side of the deltoid ridge, and from 
the outer and fore part of the middle and lower third of the humerus: it is inserted 
into the coronoid process of the ulna. The inner fasciculus of this muscle, described 
by Vrolik' in Stenops tardigradus, is wanting in Chiromys, as in Tarsius’ and Stenops 
gracilis. 
The triceps extensor antibrachii presents the same complexity as in most Quadrumana. 
" Recherches d’Anatomie Comparée sur le Genre Stenops, &c., 4to, 1843, p. 45. 
* Burmeister, op. cit. 
