MUSCULAR SYSTEM OF MAMMALIA. 



45 



21 



sertion, fig. 21, n, is anterior to that of the biceps. The massive 

 muscles answering to the ' triceps extensor ' are the ' extensor 

 longus,' figs. 20 and 21, 5, the 'ext. latus,' fig. 20, 4, the ' ext. 

 medius,' fig. 21, 6, and the ' ext. brevis,' fig. 21, 7. The ' anconeus 

 externus,' fig. 20, 6, appears to be another part of this system of 

 muscles acting on the trunk through the scapula and reciprocally 

 on the supporting limb. A small fasciculus, fig. 21, 13, arising 

 from the inner part of the distal end of the 

 humerus, and inserted into the upper 

 half of the radius, acts feebly as a flexor, 

 and seems to represent the ' pronator teres ' 

 of Unguiculates. The ' extensor carpi radi- 

 alis,' fig. 21, 12, is inserted into the fore- 

 part of the e cannon-bone.' The ' flexor 

 carpi radialis,' fig. 21, u, sends its tendon 

 behind the carpal joint to the back part of 

 the cannon-bone. The muscle, fig. 20, 10, 

 which is inserted into the inner (radial) 

 side of the cannon-bone, has an homolo- 

 gous origin with that of the ( abductor 

 pollicis.' 



The 'extensor digitorum longus,' fig. 

 20, 11, sends its two tendons in front of the 

 carpus and cannon-bone ; the inner one is 

 inserted into the middle phalanx of the 

 inner (vol. ii. fig. 193, Hi) digit ; the outer 

 tendon divides, to be inserted into the un- 

 gual phalanges of both functional digits. 

 The ' extensor brevis digitorum,' fig. 

 20, 12, is inserted into the middle phalanx 

 of the outer (ib. iv) functional digit. The 

 ( flexor carpi ulnaris,' fig. 20, is, is in- 

 serted, into the ' pisiforme ' and outer side 

 of the head of the cannon-bone. The 

 4 flexor perforans digitorum. 3 fi<>\ 21, is, Muscles of the fore-umb, Cow 



* . ' from the inner (radial) side. IV". 



sends its flat and strong tendon behind 



the cannon-bone, near the lower end of which it divides, and 

 perforates the corresponding divisions of the ' flexor perforatus,' 

 to be inserted into the ungual phalanges of the digits, Hi, iv, fig. 

 193, Ox, vol. ii. The 'flexor carpi ulnaris internus,' fig. 21, 16, 

 is inserted into the ' pisiforme.' 



The ectogiuteus, fig. 18, is, arises from the fore part of the ilium 

 and sacral fascia, and is inserted into the lower part of the great 



