PHYSIOLOGY, AND PATHOLOGY OF THK CHIMPANZEE. 349 



for the index goes under those for the second and fourth digits. 

 Ohampneys (11) states that the middle finger alone has a separate 

 radial origin, but Rolleston gives the radial origin to the tendon 

 for the index. Macalister (33) observed no radial origin at all. 

 Moore (36) states that the annularis receives two tendons, and 

 the minimus gets none. Finally, Bland-Sutton (4) describes the 

 fi.exor sublimis tendons going to the third, fourth, and fifth digits, 

 but there is a flexor sublimis indicis arising from both radius and 

 coronoid. Dvvight (18) describes a, very complex muscle. The 

 tendons split over the heads of the metacarpal bones, surround 

 the deej) flexor tendons, and are inserted as in Man into the 

 middle phalanges. 



Muscles of the Hypothenar Eminence (text-fig. 35 A & 0) : — 

 The cd)ductor minimi digiti (A.M.D) arises by a broad, but thin, 

 muscular origin from the pisiform bone. It lies along the ulnar 

 border of the hand and is inserted by a long, slender tendon into 

 the ulnar aspect of the base of the first phalanx of the little 

 finger. Its insertion is closely blended with that of the flexor 

 brevis. The flexor brevis tninimi digiti (F.B.M.D) has a single 

 head of origin fiom the anterior annular ligament and hook of 

 the unciform ; and the annular ligament a.ppears to be prolonged 

 into it. It is inserted along with the abdvictor. The opponens 

 minimi digiti (O.M.D) has a double origin from the anterior 

 annular ligament and vuicinate process of the unciform, the latter 

 being blended with the flexor brevis. It is inserted into the ulnar 

 aspect of the shaft of the fifth metacarpal bone. The palmaris 

 brevis is very extensive in both hands, but several authors 

 describe it as in Man. 



Muscles of the Thenar Eminence (text-fig. 35 A & C) : — The 

 abductor polUcis brevis (A.P.B) arises from tlie anterior annular 

 ligament, the scaphoid and sesamoid bone and the sesamoid bone 

 of the thumb, and it is divided into two slips. These unite to a 

 muscular insertion into the i-adial side of the base of the first 

 phalanx of the thumb. It conceals the lateral half of the opponens. 

 Ohampneys (11) and Macalister (33) saw no splitting into Soemmer- 

 ing's slips. The opponens polUcis (O.P) arises from the anterior 

 annuhar ligament and ridge of the trapezium. It is inserted into 

 the distal half of the i-adial aspect of the shaft of the metacarpal 

 of the thvimb. Embleton (19) states that the opponens pollicis is 

 absent. T\\e flexor brevis pollicis (F.B.P) consists of superficial and 

 deep parts. The superficial part arises by three slips from the 

 anterior annular ligament and trapezium. The deep part arises 

 from the ulnar side of the first metacarpal and anterior annular 

 ligament. Both parts unite and are inserted into the ulnar side of 

 the base of the first phalanx. The whole muscle forms a large 

 mass between the opponens superficially and the adductores deeply. 

 The adductor transversus pollicis (A.T.P) and adductor obliquus 

 pollicis (A. O.P) are as in Man. 



^he flexor longibs pollicis (F.L.P) arises fi-om the inner surface 

 of the shaft of the radius over the whole length except the 



