ANATOMY OF THE LEMUROIDEA. 39 
radius, and divides into two tendons, going respectively to the index and median 
fingers, the former being the stronger of the two. 
Cheiromys' has, according to Owen, also two tendons with a similar insertion. In 
our specimen, however, we find this muscle to be very remarkably complex. Its tendon 
is readily divisible into three parts, side by side, the middle one is the largest, and 
supplies the middle finger, but sends off a branch to the tendon of the fourth digit ; 
the radial one divides and goes to the third and index digit (that to the index being 
extremely delicate); the ulnar one of the three goes to the fourth digit only. The 
divisibility of this muscle into three is not entirely confined to the tendinous part, but 
is more or less traceable into the muscular belly itself. 
The EXTENSOR PRIMI INTERNODII POLLICIS is entirely wanting, as is also the case in all 
the Lemuroidea examined by us, as well as in Perodicticus, Tarsius, and Cheiromys. 
EXTENSOR SECUNDI INTERNODII POLLICISx—This is a long, slender muscle with a long 
tendon, and arises from the radial surface of the ulna (its origin extending as far 
upwards as behind the greater sigmoid notch), and from the interosseus membrane. 
The tendon does not receive muscular fibres lower down than the middle of the fore- 
arm, and, proceeding over the tendons of the radial extensor, is inserted into the 
proximal end of the second phalanx of the pollex. 
Figured in Galago crassicaudatus (P1. II. fig. 3, and Pl. IV. fig. 13, £.s.i.p). 
In Tarsius it is described under the name extensor pollicis longus’. 
The same in Chetromys, described by Owen under the name of extensor longus pollicis‘. 
EXTENSOR OSSIS METACARPI POLLICIS’.—This is a large and flat muscle arising from the 
middle four sixths of the posterior surface of the radius and from the interosseous 
ligament. Its very strong and flat tendon crosses those of the radial extensors, and, 
passing through a groove in the outermost part of the back of the radius, is inserted 
into the outer side of the base of the metacarpal of the pollex. 
Substantially the same in Galago, Loris, Nycticebus®, Tarsius, and Cheiromys. Figured 
in Galago crassicaudatus (PI. I. fig. 3, and Pl. IV. figs. 13 & 14, E.o.m.p). 
e. Brachial Region ( flexors). 
PRONATOR RADII TERES.—This muscle is largely developed, and has an exceedingly 
tendinous surface, especially towards its insertion. It arises from the internal condyle 
1 Loc. cit. p. 62. 
? The tendon of this muscle is shown by Cuvier, pl. 69. fig. 1, Z, in Z. varius, and pl. 67. fig. 1, Z, in Loris 
gracilis. 
3 Loc. cit. p. 63, tab, 3. tig. 4. 37, 4 Loc. cit. p. 62, pl. xxiii. fig. 2, no. 37. 
5 Magnificent as is the posthumous work, on Myology, of Baron Cuvier, it nevertheless leaves much to be 
desired. Thus there is no view of the deep muscles of the forearm of the Lemuroids represented; so that this 
muscle, like the preceding and some others, has only its distal portion shown cropping out from beneath the 
superficial muscles. See pl, 69. fig. 1,1, Z. varius; pl. 67. fig. 1,4, Loris gracilis. 
5 P, Z. §. 1865, p. 248, 
