of the Koala (Pliascolarctos cinercus). 133 



Tihialis post icus is double : — a larger muscle, placed rather more 

 superficially, and inserted anteriorly into tlic sesamoid at the 

 base of the hallux ; a smaller, deeper muscle, inserted into the 

 entocuneiform and second and third metatarsals. 



The perforated flexor of the toes was a very remarkable 

 muscle ; it lay, not in the foot as usual, but on the back of the 

 leg, arising from the surface of the flexor p-ofundus for the 

 lower half of the leg, exactly like its homotype the flexor suh- 

 limis in the forearm ; its fleshy portion does not extend below 

 the ankle ; but its tendons pass to the second, third, fourth, 

 and fifth toes. There is wo flexor accessorius in the foot; but 

 a muscle, evidently similar to this in nature, passes from the 

 calcaneum to the sesamoid at the base of the hallux. 



There is a long jjerona'us which arises from the upper half of 

 the fibula and from the sesamoid bone oi\[\t gastrocnemius exter- 

 n us ; this is inserted as usual. Peronamshrevis is also normal, and 

 quite separate from the peronccus qiiinti^ below which it arises. 

 There is also a, jjeronams quarti metatarsi in front of the quinti, 

 perfectly separate from it and placed behind the malleolus. 



Tibialis anticus and extensor hallucis are normal. The ex- 

 tensor cligitorum sends oiF four tendons ; but those for the 

 second and third digits arc connected until very close to their 

 insertion. 



On the back of the leg there is a large pronator quadratus 

 like that in the leg of other Marsupials and the crocodile; this 

 occupied more than half the length. 



The foot-m-uscles are the following : — For the hallux there 

 is an ahductor^ a bicipital _/7ej:'or hreris^ an opponens (from the 

 inner cuneiform to the metatarsal), and an adductor (from the 

 second metatarsal to the hallux) ; there is also an " interosseus 

 primus volar is j^^ like Henle's interosseous in the manus. For 

 the little finger there is an abductor proper and a separate ab- 

 ductor ossis metatarsi minimi digiti (Flower), There is no 

 Jumbricalis for the second digit ; that for the third comes from 

 the tendon for the third digit alone ; that for the fourth comes 

 from the third and fourth tendons ; and that for the fifth comes 

 from the fourth tendon. 



The interossei are arranged as follows : — The dorsal are : 

 (1) abductor indicis, bicipital ; (2) abductor 7nedii, bicipital ; 



(3) abductor quarti^ also two-headed ; (4) abductor quarti, with 

 only one head from the fourth metatarsal. The palmar are : 

 (1) adductor hallucis, as before mentioned ; (2) adductor 

 tndicis ; (3) adductor (?) medii, from the second metatarsal to 

 the fibular side of the third, Avhosc metatarsal it crosses ; 



(4) adductor minimi digiti. There is also a very small ojpo- 

 nens minimi digiti inserted into the metatarsal of the fifth toe. 



