8J- ORTGIXAL RETICLES. 



muscular layei', arising fi'om the palmar ligament wliicli formed three 

 small muscular digitations, which were inserted into the radial side 

 of the first phalanx of the fourth and fifth digits, and the third into 

 the ulnar side of the first phalanx of the index. A similar muscular 

 expansion was found in the feet of these monkeys. 



The Pahnnris Brevis was, I think, absent, but as the animal had 

 been skinned before I examined it, the muscle may have been cut 

 away. Dr. Traill found none in the one he dissected. In the Chim- 

 panzee it is present (Vrohk, 1. c. p. 20). It was remarkably large in 

 the Magot, arching over the whole of the carpal portion of the hand, 

 reaching from the external side of the little finger to the internal 

 side of the thumb ; it was present also in the Cebus. 



The Abductor, Flexor Brevis and Opponens Minimi Digiti pre- 

 sented no peculiarities worth notice. 



The Dorsal Inte^rossei presented the same general appearance as 

 in man, only differing in the greater development of the Abductor 

 Indicis ; but the palmar set differed considerably, being seven in num- 

 ber ; the index possessed two, the radial one being a broad flattened 

 muscle, which arose from almost the whole length of the metacarpal 

 bone of that finger, and was inserted into the upper and inner side of 

 the metacarpal of the pollex ;t the one on the ulnar side arose from the 

 under and inner surface of the metacarpal of the index, and was in- 

 serted into the first phalanx of the sam.e finger ; the middle and ring 

 fingers had each two and the little finger one, similar muscles. In both 

 the Cebus and Magot the dorsal muscles resembled man's, but the 

 palmar ones closely resembled those of the Carnivora; they were also 

 seven in number, and arose from the pahnar ligament, as well as 

 from the metacarpal bones, which they completely hid from view. 



The hand of the Orang and of the Chimpanzee appears at first 

 sight to be less perfectly organized than that of some of the other Qua- 

 drumana, owing to the total absence of any long flexor of the thumb ; 

 the absence of this muscle permits of a greater independence of motion 

 in their thumbs than in any of the other monkeys, in which the long- 

 flexor exists as a portion of the Profundus. In the Orang and Chim- 

 panzee the great development of the Abductor, and the well marked 

 Flexor Brevis in some degree make up for the absence of the long 

 flexor. The double adductor has been observed in man (M'Whinnie). 

 Wagner, when speaking of the hand of the Quadrumana, says : 

 " The individual mobility of the fingers is much more limited than in 

 man, and this is more particularly the case with the thumb."* This 

 is perfectly true of lower Quadrumana, as is shown in the case of the 

 Cebus, but I think in the Baboons and Magots the greater develop- 

 ment of the muscles of the thumbf proves that they can move the 



* Elements of the Comparative Anatomy of Vertebrate Animals. 11. Wagner, 

 p. 18. Translated by Talk. 



•f This appears to conespond with the Musculus interosseus volaris primns — (a 

 fourth palmar interosseus) described by Henle, 1. c., p. 228, as constant in the 

 himian liund. — [Eds.] 



