136 PHYSIOLOGICAL SERIES. 



The two portions of the adductor pollicis (transversus and 

 obliquus) are entirely distinct. 



Presented l>y Jolm Marshall, Esq. 



C. 170. Left fore-limb of the same Chimpanzee, showing the 

 nerves and deep muscles. The pectoralis minor is attached 

 to the head of the humerus. The coraco-brachialis is 

 represented by the medius, perforated by the musculo- 

 cutaneous nerve. The flexor carpi radialis has a supple- 

 mentary tendon of attachment to the trapezium (indicated 

 by a black bristle). The radial segment of the flexor pro- 

 fundus supplies the index and gives off a small muscular 

 slip and tendon (flexor longus pollicis) to the thumb. The 

 fourth lumbrical has a double origin from tendons IV. & v. 

 of the flexor profundus. Presented by John Marshall, Esq. 



C. 171. Left elbow of a Chimpanzee (Anthropopithecus troglo- 

 dytes) , showing the supinator brevis. The muscle is broken 

 up into several laminae, distinguishable mainly from the 

 different course of their muscle-fibres, and is overlaid by a 

 remarkable sheet of muscle (indicated by a blue rod) that 

 rises from the outer side of the humerus close above the 

 eondyle beneath the extensor carpi radialis, and is inserted 

 into the radius with the distal part of the underlying 

 supinator brevis. 



C. 172. Deep muscles of the left hand and distal part of the arm 

 of a Chimpanzee (Anthropopithecus troglodytes) . The rudi- 

 mentary tendon that represents the flexor longus pollicis 

 rises from the sheath of the flexor profundus tendon n. 

 Besides the usual three adductor palmnr interossei, there are 

 also upon this surface of the hand four abductor interossei 

 attached to the sides of the first phalanges of digits II., HT., 

 iv. (blue rods are placed beneath their tendons). These 

 muscles are probably not true palmar interossei, but slips 

 from the dorsal interossei that have migrated to the palmar 

 surface. Each of the extensors of the thumb is inserted 

 one bone above its usual human attachment. 



Hepburn, Trans. R. Soc. Edinburgh, vol. xxxviii. 1897, 

 p. 557 ; Keith, Nat. Sci., vol. ix. 1896, p. 251. 



