1865. ] ANATOMY OF NYCTICEBUS. 247 
In Cheiromys* there is a very interesting intermediate condition. 
The arrangement much resembles that existing in Nycticebus ; but 
the two muscles are not nearly so distinct. There is only one ten- 
don to the pollex, and the muscular fibres arising from the middle of 
the ulna join the part which answers to the flexor longus pollicis. 
The extensor communis digitorum and extensor minimi digiti ap- 
pear to be represented by only one muscle, which arises by a diminu- 
tive tendon from the external condyle of the humerus. The mus- 
cular fibres give origin to a tendon which soon becomes divided into 
two; the radial one of these again subdivides into four very fine 
tendons, one going to the index, another (the broadest) bifurcating, 
its branches going to the third and fourth digits respectively ; an- 
other (the third subdivision) goes to the fourth digit, and the last to 
the fifth digit. 
The ulnar main division of the common tendon goes to the fifth 
digit only. This last perhaps answers to the extensor minimi 
digiti, or that portion of the extensor communis recorded by Profes- 
sor Owen’ as existing in Chetromys, and sending subsidiary tendons 
to the fourth and fifth digits. 
Fig. 4. 
Enlarged view of the palmar surface of the hand, to show the small muscles of 
the pollex and fifth digits; also the interossei and insertions of the lum- 
bricales. 
The extensor indicis is a very small muscle arising from the mid- 
dle of the ulna at its radial side, and from the interosseous mem- 
brane, It gives origin to two tendons, one going to the index, the 
' Owen, Trans. Zool. Soc. vol. v. p. 63, pl. xxiii, fig. 4. 
* Loe. cit. p. 62, pl. 23. fig. 2. no. 27a. 
