THE MYOLOGY OF THE ANTHROPOMOEPHA. 483 



maniis. The flexor pollicis is more or less closely connected 

 with the flexor communis perforans, or with that jDart of the 

 muscle which goes to the index digit. The connection is 

 slightest in Hylohates, the origins of the two muscles, only, 

 being imited. It is most extensive in the Orang, in which 

 no tendon goes to the pollex. The same complete loss 

 of the flexor pollicis, as a thumb muscle, occasionally takes 

 place in the G-oi-illa ; but in this animal, as in the Chimpan- 

 zee, the rale appears to be, that the flexor pollicis unites at 

 its origin with part of the flexor perforans, and that the 

 fleshy fibres converge to a common tendon which divides into 

 two, one for the poUex and the other for the index. In 

 Hylobates, the short head of the biceps brachii arises from the 

 pectoralis major, and the adductor hallucis and transversus 

 pedis form but one miiscle. 



The flexor longus liallucis takes an origin from the ex- 

 ternal condyle of the femur in the Orang ; and the pecto- 

 ralis major arises by three distinct slips. 



Some of the muscles in the Anthropomorplia differ in 

 their insertion, or in the extent to which they are sub- 

 divided, from what is usual iu the corresponding muscles of 

 Man. Thus the extensor ossis metacarpi pollicis ends in two 

 . distinct tendons ; one for the trapeziiim, and the other for 

 the base of the metacarpal bone of the pollex. That part 

 of the tibialis anticus which goes to the metatarsal of the 

 hallirs is usiially very distinct, and is sometimes reckoned 

 as a separate muscle, the abductor longus hallucis. 



In the Gibbons and in the Orang, there is a complete sec 

 of deep extensors for the four ulnar digits, the tendons of 

 the extensor indicis and extensor minimi digiti subdividing 

 to supply the third and fourth digits. 



In the Gordla and Chimpanzee each of these muscles have 

 but a single tendon, as is the usual arrangement in Man. 



The interossei. of the hand are each divided into two 

 muscles with distract tendons — a flexor brevis primi inter- 

 nodii and an extensor brevis tertii internodii. The division is 

 less obvious in the Orang than in the other Anthropo- 

 morplia. 



