Of THE KOALA. AND VTJLPINE PHALANOER, 553 



IVichosurus vulpecula (text-fig. 57). 



The deep anatomy of the neck differs from that of Phasco- 

 larctos in the following respects ; — 1. The walls of the mouth 

 and pharynx aie move deeply placed under mviscles. 2. True 

 hyoglossus muscles are present (B), so the lingual ai-tery (c) and 

 hypoglossal nerve (d) are more deeply placed. 3. The thyroid 

 gland is applied to the posterior part of the larynx and is far 

 antei'ior ; it does not pass dorsal to the clavicles. 4. The 

 alisphenoid bullse are not so prominent. The exoccipital pro- 

 cesses are not visible. 5. The external jugular vein is formed on 

 the surface of the sternomastoid muscle. 



The Respiratory Organs. 



In Phascolarctos the epiglottis is broad and entire, with an 

 emai'ginate apex, and each lung contains two lobes ; Forbes (4) 

 described two left and three right lobes. JSTo azygos lobe is 

 present. In Trichosurus the epiglottis is notched ; the left lung 

 has two lobes and the right one has four, of which one is azygos. 

 The tracheal rings are wide, but deficient dorsally. 



The nasal tube of Phascolarctos has no median dorsal ridge, 

 and does not grip the larynx, whose epiglottis is so large that it 

 could only be accommodated by considerable stretching of the 

 orifice of the tube. 



In Trichosurus the nasal tube has a median dorsal ridge, and 

 it gripped the larynx firmly in my specimen. 



Sir Evei'ard Home states that the Koala utters a shrill yell 

 when hungry or hunted, but Owen says that he never heard a 

 note of any kind from the Phalangers. 



The Mouth. 



Phascolarctos cinereus. 



The Vestibule. — Fleshy lips are connected to the gums by lax 

 frenvims, of which the upper is "6 and the lower is 1*2 cm. long. 

 The cheeks are attached to the gums opposite the canine tooth 

 and posterior border of the premolar of the upper jaw on each 

 side ; between these lie the mouths of the cheek-pouches 

 (Plate v., A) already described by Owen (11), Young (13), and 

 Forbes (4). 



Forbes states that " the mucosa of the cheeks is smooth 

 throughout " ; but in my specimen it is covered with rounded 

 papillae, which are all visible to the naked eye. They extend on 

 to the fauces, and for a short distance along the outer walls of 

 the cheek-pouches, but they are absent from the lips whose 

 mucosa is quite smooth. They are not regularly arranged like 

 the papillae of the cheeks of the Ungulata. 



