REPORT ON THE MARSUPIAL! A. 145 



plantar nerves. The gastrocnemius receives two of its muscular branches — one to each of 

 its heads, whilst the popliteus appropriates no less than three. These enter its upper, 

 middle, and lower portions respectively. The second of these proceeds downwards in the 

 interval between the tibialis posticus and flexor longus digitorum, and the third between 

 the tibialis posticus and the flexor longus hallucis. 



In the right leg the plantaris was supplied by two twigs from the external plantar nerve. 



In Cuscus the same muscular branches (PI. V. fig. 2, 5) are given by the internal 

 popliteal, but the nerve ends by dividing into three, viz.: — (l) a nerve to the hallux (7) ; 

 (2) internal plantar (6) ; (3) external plantar (3). 



The nerve of the hallux is present only in Cuscus. It runs downwards alongside the 

 internal plantar nerve between the superficial and deep muscles on the back of the leg. 

 Near the ankle it diverges inwards, leaves the internal plantar nerve, and is distributed 

 to the hallux by a dorsal and a plantar branch (PL VI. fig. 8, 4, and fig. 5, 1). The 

 dorsal branch joins the inner of the three terminal twigs of the internal saphenous, and 

 is distributed upon the tibial margin of the digit ; the plantar branch pierces the inner 

 edge of the abductor hallucis which it supplies, and then forms the inner collateral plantar 

 twig for the hallux (PI. VI. fig. 7, 1). This branch in one limb was joined by a filament 

 from the internal plantar nerve. 



Internal 'plantar nerve. — The internal plantar nerve runs down the back of the lee 

 between the superficial and deep muscles, and enters the sole by passing behind the 

 internal maleolus. 



In Thylacinus it now proceeds along the inner margin of the flexor brevis digitorum, 

 and, sinking under cover of the plantar fascia, divides into three digital branches, which 

 are distributed in the following manner (PL VI. fig. 4, 2) : — (1) the first goes to the 

 tibial side of the index ; (2) the second, which is reinforced by a long slender twig from 

 the deep division of the external plantar, bifurcates to supply the adjacent margins of 

 the index and medius ; (3) the third divides and supplies the contiguous margins of the 

 medius and annularis. From the main trunk several small twigs are given to the flexor 

 brevis digitorum, whilst from the digital nerves no fewer than ten branches are supplied 

 to the plantar pad. 



In Cuscus the internal plantar at the ankle sends a recurrent branch (PL V. fig. 2. 8) 

 to the flexor brevis digitorum, and a communicating and reinforcing twig to the plantar 

 portion of the nerve to the hallux. It then enters the sole by passing under cover of the 

 plantar cartflage, and, after sending branches to the flexor brevis hallucis, divides into three 

 digital branches, which have the following distribution : — (l) the first bifurcates to supply 

 the adjacent sides of the hallux and index ; (2) the second divides for the supply of the 

 contiguous and adherent sides of the index and medius ; and (3) the third goes to the 

 adjacent sides of the medius and the large annularis, and in addition communicates with 

 the inner digital branch of the external plantar (PL VI. fig. 7, 2). 



(ZOOL. CHALL. EXP. PART XVI. 1882.) Q 19 



