888 MR. F. G. PABSONS ON THE [NoV. 29, 



minimus ; the more radial one supplies the thenar muscles and 

 reinforces the second and third digital clefts. 



The ulnar nerve comes from the inner cord and runs down on 

 the inner side of the brachial artery, passes deep to the epitrochleo- 

 ancoueus muscle, which it supplies, and in the forearm only supplies 

 the flexor carpi ulnaris and the flexor sublimis digitorum, 

 no branch being given to the flexor profundus. After this the 

 nerve passes to the deep part of the hand and supplies all the muscles 

 of the palm except those of the thenar eminence. The usual 

 dorsal cutaneous branch is given off' to supply one and a half digits 

 on the ulnar side of the hand. It will thus be seen that in this 

 specimen of Pedetes there has been an exchange of fibres usually 

 bound up in the ulnar and median nerves respectively. The flexor 

 sublimis digitorum is entirely supplied by the iilnar, an arrangement 

 which has already been observed in many mammals by Professor 

 K. von Bardeleben ; but, on the other hand, the whole of the flexor 

 profundus digitorum and all the digits on their palmar surfaces 

 are supplied by the median. 



The internal cutaneous nerve comes from the inner cord and 

 supplies the skin of the inner side of the arm and forearm. There 

 is no separate lesser internal cutaneous, but the lateral cutaneous 

 branch of the second intercostal (intercosto-humeral) crosses the 

 axilla and supplies the skin of the upper part of the inner side of 

 the arm. 



The internal and external anterior thoracic nerves come off" from 

 the internal and external cords respectively and form a loop from 

 which the pectorals are supplied ; from the internal anterior 

 thoracic a large branch (lateral cutaneous nerve of the thorax) 

 passes back to supply the abdomino-humeralis portion of the 

 panniculus as well as part at least of the pectoralis quartus'. 

 The musculo-spiral nerve derives fibres from the dorsal divisions 

 of all the trunks entering the brachial plexus ; that, however, from 

 the first thoracic joins it, after the circumflex and subscapular 

 branches have been given off ; the nerve winds round the back of 

 the humerus as usual, supplying the triceps, latissimo-olecranalis, 

 anconeus, and skin of the back of the arm and forearm, but no 

 branch is given to the flexor brevis cubiti (brachialis anticus). In 

 front of the external condyle it divides as usual into radial and 

 posterior interosseous, the former supplying three and a half 

 radial digits on their dorsal surfaces, the latter all the extensor 

 muscles of the forearm. 



The circumflex nerve comes ofE from the combined dorsal 

 divisions of the 5th and 6th nerves, so that it can only obtain 

 fibres from these. It pursues the usual course and supplies the 

 teres miuor and all three parts of the deltoid. 



The middle and lower subscapular nerves rise from the musculo- 

 spiral before the dorsal division of the first thoracic has joined 

 that nerve. The middle subscapular supplies the latissimus dorsi 



^ Professor Birmingham has published a masterly discussion on this subject 

 in the ' Journal of Anatomy,' vol. xxiii. p. 206. 



