132 



by I. in the figures) which crosses the head at the anterior (superior) attachment 

 of the auricle, and is continued down the side of the face and to the throat just 

 in front of the ear. Caudad of this line the hair is directed forward, streaming 

 directl)' ccphalad on to the occiput, outwards on the dorsum of the auricle, and 

 downwards and forwards on the neck. These cephalad pointing hairs are part 

 of a whorlcd system (marked II.) which takes its rise upon the mid line of the 

 back between the attachments of the two fore limbs. The vortex lies practically 

 in the middle line, and the stream of hair points counter-clockwise. Hair from 

 the vortex streams cephalad, as we have seen, and also downwards and forwards 

 on the chest, downwards and caudad on the fore limbs, and directly caudad to 

 the lower limit of the thorax. At the lower costal margin this caudally-directed 

 stream meets a directly reversed stream at a well-marked line of convergence 

 (marked III.), which passes from the dorsal region around the flanks and 

 abdomen in front of the hind limb. The hair which streams cephalad to this 

 line emanates from bilateral vortices (IV. and IV.^), situated close to the middle 

 line over the sacral region. Of these two vortices the one on the left side is 

 disposed counter-clockwise, and the one on the right side clockwise. This 



Phascolarctus cincreus. 

 Characters of the external ear. 



disposition leads to the production of a mid dorsal convergent stream-line 

 cephalad to the whorls (between them and the costal margin) in which the hair 

 is directed cephalad and towards the mid line ; and a mid dorsal convergent 

 line caudad of the whorls in which the hair is directed caudad and towards the 

 mid line. A little peak of hair marks the site of the absent tail. From the 

 sacral vortices the hair streams downwards, with a general post-axial trend, 

 upon the thigh and leg. Upon the front, and rather to the fibular side of the leg, 

 and just above the ankle, is a further partially whorled area (marked \'., in 

 fig. 1). At this area of reversal, the hair streams upwards upon the fibular side 

 of the leg, and, meeting the downward convergent stream from above, produces 

 a well-marked convergent line, a divergent area being situated just above the 

 flexure of the ankle. Upon the fore limb there are no reversals ; but the post- 

 axial convergent stream is particularly well marked. 



Sensory I'ibrissac and Papillae. — Over the whole body, the sensory vibrissae 

 and papillae are peculiarly reduced. The facial vibrissae are represented by 

 sparse and reduced members of only three of the typical five sets. The mystacial 



