the Wombat and Tasmanian Devil. 165 



Sarcophthis extends from the lower end of the ulna to the 

 index, middle, and ring fingers, completing thus the third 

 group of extensors for the digits. A small slip passes from it 

 to the thumb, similar to the extensor pollicis et indicis of the 



Dog. 



The supinator brevis occupies the upper two-thirds of 

 the radius in the Wombat, the upper third in Sarcophilus, the 

 Wallaby and Giant Kangaroo, and the upper fourth in the 

 Opossum; in all it has a condylar origin. In none of these does 

 its insertion reach to such an extent as in Echidna hystrix^ in 

 which it occupies the entire length of the radius, and balances 

 the pronator radii teres. 



The alxluctor pollicis is very small in Phascolomys, is mo- 

 derate in size in Sarcophilus, but, as a rule, small in the other 

 marsupials, except in the Opossum — in which all the thumb- 

 muscles are particularly well developed, an opponens pollicis 

 being present in it, although suppressed in all the other mar- 

 supials which I have dissected. 



The palmaris brevis in the Wombat is absent ; but in the 

 Tasmanian Devil a slip representing it arises from the pisiform 

 bone, and is lost over the tendons of the tlexor muscle of the 

 digits. In no animal have I seen this miLscle so curiously 

 displaced as in Echidna hystrix; for in a fine specimen of this 

 animal dissected by Professor Haughton and myself, Decem- 

 ber 29, 1869, this muscle, or a small one like it, arose from 

 the ulna for a quarter of an inch above its lower end, and was 

 lost in the fascia over the tendons of the wi'ist. 



The lumbricales are four in number in the Wombat and 

 Sarcophilus J one passing from the flexor tendon to the polliceal 

 side of each digit ; they are similarly arranged in Phalangista^ 

 Perameles, and Didelphys. 



The palmar interossei in the Wombat and Sarcophilus are 

 four in number : — the first, or Henle's interosseus primus vo- 

 laris ; the second, to the ulnar side of the index ; the third, to the 

 radial side of the annularis ; the fourth, to the radial side of the 

 little finger. The dorsal interossei are five in number : — first, 

 abductor of the index, from the first and second metacarpal to 

 the first phalanx of the index ; second, from the second and 

 third metacarjials to the middle finger ; third, from the third and 

 fourth to the middle finger ; fourth, from the fourth metacaqjal 

 to the ring-finger ; and fifth, from the fifth metacarpal to the 

 little finger ; this last is extremely small in the Wombat — 

 indeed, reduced to an excessively delicate thread. 



The external oblique arises, in the Wombat, Macropus, and 

 Phalangista, from the eight lower ribs and lumbar fascia, and, 

 passing inward, is inserted into the border of the ilium, into 



