

BY WILLIAM A. HASWELL, M.A., B.SC. L81 



The piriformis is quite a distinct muscle in Phalangista (as well 

 as in Petaurista and in Cuscus) and is not amalgamated with the 

 gluteus inedius as stated by Professor Macalister. (1) 



The arrangement of the biceps described by Cunningham a l 

 obtaining in Cuscus is almost identical with that observed in 

 Phalangista and Petaurista. The muscle consists of an ischial 

 part arising with the semitendinosus from the ischial tuberosity 

 and spreading out in a triangular form distally to become inserted 

 into the fascia of the leg ; and a caudal part which arises from the 

 transverse processes of the first two caudal vertebrae, and, after 

 becoming closely united for a short distance with the semitendi- 

 nosus, bifurcates— one part joining the ischial division of the 

 muscle and the other becoming inserted into the inner side of the 

 tibia. In all three genera the bicipiti accessorius is absent. 



In Petaurista and Phalangista the rectus femoris has only a 

 single head ; in Cuscus Cunningham describes a slender second 

 head arising from the spine of the ilium. In the Koala, 

 Macalister describes the origin as single. (2) 



In Phalangista, as in Cuscus, the gracilis has no connection with 

 the marsupial bone. In Petaurista on the other hand a few fibres 

 are derived from the base of that bone. 



Cunningham describes only two adductors as occurring in Cuscus 

 — the adductor brevis and the adductor magnus ; but in both Pha- 

 langista and Petaurista all three adductors are well represented. 



In Cuscus and Phalangista the gastrocnemius consists of two 

 parts which are separable throughout, the inner part arising from 

 the back of the internal condyle of the femur, while the outer derives 

 its origin from the sesamoid at the head of the fibula and from the 

 outer condyle. In Petaurista the muscle has the same origins, but 

 the two halves are intimately united in the middle of the calf. 



(1) " Myology of the Wombat and Tasmanian Devil," Ann. Mag. Nat. 

 Hist. (4th series), Vol. V., p. 167. 



(2) " Muscular Anatomy of the Koala." Ann. Mag. Nat. Hist. (4), X. 



