176 JOTTINGS FROM BIOLOGICAL LABORATORY, SYDNEY UNIVERSITY, 



JOTTINGS FROM THE BIOLOGICAL LABORATORY OF 

 SYDNEY UNIVERSITY. 



By William A. Haswell, M.A., B.Sc. 

 Lecturer on Zoology and Comparative Anatomy. 



6. On the Myology of the Flying Phalanger. 



(petaurista taguanoides.) 



Petaurista is a Phalanger which has undergone a modification 

 strictly paralleled by that observable in the case of the true Flying 

 Squirrels. A wide flap of skin extending on either side of the 

 body between the fore and the hind limbs enables the animal, by 

 straightening the limbs and extending the front pair forwards and 

 the hind pair backwards, to present a broad flat surface to the air, 

 by the parachute action of which it is enabled to fly, or rather 

 skim, in a slanting direction from one branch to another. 



An examination of the muscular system of this curious Marsupial 

 shows that it is in all essential respects, as in fact is evidenced by 

 the structure of the skeleton and the dentition, a very near ally of 

 Phalangista and of Cuscus. The special modifications of the muscles 

 connected with the act of so-called flight are very few and, with the 

 exception perhaps of the remarkable femoro-caudal muscle, concern 

 only the panniculus carnosus. 



Muscles of the Anterior Extremity. 



As in many other Marsupials the differentiation of the deltoid 

 from the trapezius is incomplete — a portion of the fibres of the 

 latter passing over the shoulder and taking the place of part of 

 the former. In other words the anterior part ot the trapezius in 

 Petaurista, instead of stopping short at the acromion and clavicle, 



