MYOLOGY AND CLASSIFICATION OF THE WOMBAT, ETC. 863 



38. On the Myology and Classification of the Wombat, 

 Koala, and Phalangers. By Charles F. Sonntag, 

 M.D., F.Z.lS,, Anatomist to the Society, 



[Received August 1, 1922 : Read November 7, 1922.] 



(Text-figm-es 31-43.) 



Contents. 



Page. 



Introduction 863 



Myology 863 



Classification 886 



Bibliography 895 



Introduction. 



The most remarkable features in the existing classifications of 

 the Diprotodont Marsupials* are the positions assigned to the 

 Wombat, Koala, and Phalangers. Some zoologists have included 

 the Koala in the Phalangeridse and kept the Wombat separate. 

 Others have included the Koala and Wombat in the Phas- 

 colarctidse. And others again have formed three families — 

 Phalangeridse, Phascolarctidse, and Phascolomyidse. It is evident, 

 therefore, that there is considerable difference of opinion as to 

 the true positions of these animals. To form a lasting and 

 natural classification one must examine all anatomical data, so as 

 to exclude convergent and adaptive characters, and those which 

 represent varying degrees of persistence of primitive conditions 

 which were present in their common ancestor. The exclusion of 

 these conditions, leaves us with data which are of vahie for 

 purposes of classification. And these can be divided into major 

 and minor groups. Minor characters are employed to emphasise 

 the classification based on major ones. 



In the examination of animals received at the Society's 

 Prosectorium t I observed so many points in their myology 

 hitherto unrecorded, or different from existing accoimts, that I 

 have considered it fit to set them down as a separate section in 

 this paper. As the anatomy of the skeleton, teeth and viscera is 

 already well known I have simply mentioned the most distinctive 

 characters in the section on classification. 



Myology. 

 Muscles of the Head and Neclc. 

 The Platysma in all species is muscular in the face and neck. 

 It is continuous with the facial, orbital, and auricular muscles, 



* Pocock (9) and Osgood (7) have reproduced most of the systems of classification 

 vi'hich have been proposed. 



t Fhascolomys mitclielli ((?$), Fhascolarctos cinereus ( $ ), Phalanger orientalis 

 (adult female and female mammary foetus), Fseridochirus peregrinus ( ? ? $ ). 

 Many points in the anatomy of Trichosuriis vulfecula have been described by me in 

 a former^aper (10). 



