REPORT ON THE MARSUPIALIA. 31 



downwards, and passing under cover of the flexor carpi radialis and the anterior annular 

 ligament, enters the palm. It gives off no branches in the forearm. In the Thylacifie 

 the palmar branches are very numerous. Eight distinct twigs are given to the palmar 

 pads, and then the nerve ends in digital branches which supply the palmar aspect 

 of all the fingers with the exception of the radial side of the thumb and the ulnar side 

 of the little finger. In the Cuscus the branches to the skin of the palm are not so 

 plentiful, and digital twigs are only given to the index and middle fingers and to the 

 ulnar side of the thumb and the radial side of the ring finger. In both animals 

 the median nerve supplies all the lumbrical muscles. It also communicates freely with 

 the palmar branches of the ulnar nerve on the one hand and medio-radial nerve on the 

 other. 



The ulnar nerve (PI. I. fig. 6, u. ; PI. II. fig. 4, u.n. ; PI. II. fig. 3, u.n.) crosses the 

 axillary vein, and running down the inner aspect of the limb to the interval between the 

 olecranon and internal condyle of the humerus, it enters the forearm by passing under 

 cover of the anconeus internus. In the forearm it lies between the ulnar flexor of the 

 carpus and the ulnar part of the flexor muscle, and it ends at the junction of the middle 

 and lower thirds of the forearm by dividing into a palmar (PL II. fig. 3, u.n.) and a dorsal 

 branch. It supplies the anconeus internus, flexor carpi ulnaris, and a few small twigs 

 proceed from it to the ulnar and condylar parts of the flexor muscle. 



The palmar portion of the nerve, as it approaches the pisiform bone, divides into a 

 superficial and a deep division. The former goes to the ulnar margin of the hand, 

 supplies the abductor minimi digiti, and then proceeds onwards as the palmar digital 

 branch for the ulnar side of the little finger. The deep division crosses the annular 

 ligament superficially, under the shadow of the pisiform bone, and enters the palm. 

 It at once sinks under cover of the ulnar head of the flexor brevis minimi digiti, and turning 

 outwards is carried across the palm towards the radial margin of the hand between the 

 plantar and intermediate strata of intrinsic muscles. It is expended in the supply of all 

 the adductors, the dorsal interossei, and the short flexors, with the exception of the flexor 

 brevis pollicis. In the Cuscus it supplies, in addition to these muscular twigs, the digital 

 branch for the adjacent sides of the ring and little fingers. This nerve emerges from 

 under cover of the adductor annularis (PI. II. fig. 3, d.n.). In both it gives off branches 

 to the skin of the palm. 



The dorsal branch of the ulnar nerve winds round the ulnar margin of the forearm 

 under cover of the tendon of the flexor carpi ulnaris, and it ends in digital branches for 

 both sides of the little finger and the ulnar side of the ring finger. 



The number of nerves which are given to the skin of the palm in the ThyUtcine is 

 very surprising. Each of the three palmar nerves contributes to its supply — the median 

 alone giving eight twigs. This seems to indicate that the palmar skin possesses an 

 unusually high degree of sensibility. 



