REPORT ON THE MARSUPIALIA. 25 



brevis pollicis (fig. 3, r/ 1 ) and flexor minimi digiti (fig. 3, y h ) are exceptions to this rule, 

 as both slips of each of these muscles are fixed directly to the bone. 



The opponens minimi digiti is very distinct, but fused with the ulnar part of the short 

 flexor. It is inserted into the lower half of the ulnar margin of the metacarpal bone of the 

 little fingei\ This insertion is quite continuous with that of the short flexor of the same 

 finger into the ulnar face of the first phalanx. There is no trace of an opponens pollicis. 



The foregoing observations upon the intrinsic muscles of the hand are based upon 

 four dissections of the manus of the Thylacine, two of the Cuscus, and one of the 

 Phascogale. In addition I have also examined the hand of the Vulpine phalancjer, the 

 Dasyurus viverrinus, and the Australian wild Dog or Dingo, with the view of comparing 

 the same muscles in them with those of the animals in which I was more specially 

 interested. 



The Vulpine phalanger in its hand muscles closely resembles the Cuscus, but the 

 adductor or palmar group is feebly represented, and consequently the median raphe is 

 not so well seen. The flexor brevis pollicis and the flexor brevis minimi digiti are 

 apparently only represented by their radial and ulnar heads respectively, but these are 

 strongly developed. 



An opponens minimi digiti in all respects like that of the Cuscus is to be found, also 

 a few fibres passing to the metacarpal bone of the thumb from the short flexor of that 

 finger. The latter may represent an opponens pollicis. 



The Dasyurus, on the other hand, agrees with the Phascoyale. It has a powerful 

 palmaris brevis similar to the same muscle in the Thylacine, and like the Vulpine 

 phalanger it seems to be deficient in the adducting portions of the short flexors of the 

 thumb and little fingers. 



In the hand of the Dingo the metacarpal bones are compressed together so as to 

 obliterate the intermetacarpal spaces, and in consequence of this the interossei muscles 

 are situated in the palm. The clear definition between the three groups of muscles is 

 therefore lost, more or less complete fusion of certain muscles takes place, and the 

 arrangement is more difficult to interpret. 



The abductors of the little finger and thumb are both present, but the latter is very 

 rudimentary, like the digit upon which it acts. The four dorsal interossei lie upon the 

 palmar surface of the metacarpal bones, and are fused to a certain extent with the 

 representatives of the intermediate muscles in the Marsupials. They are poorly developi-d, 

 and have the same insertions as the corresponding muscles in man. 



The palmar muscles are three in number — (1) adductor pollicis, a very minute slip; 

 (2) an adductor indicis ; (3) an adductor minimi digiti. 



The intermediate flexors are very similar to the same muscles in Marsupials, but the 

 flexor brevis pollicis is suppressed, and the minute pollex is in this case flexed by the 

 combined action of its abductor and adductor. 



(ZOOL. CUALL. EXP. PART XVI. 18S2.) Q 4 



