OF TUE KOALA AND VULPINE PHALANGER. 557 



TiHchosurus vidpecula. 



Poulton (16) described the tongue under the old name of 

 Phcdangista vidjnna, so I shall only mention the differences 

 between it and that of Phascolarctos : — 1. The epiglottis overlaps 

 the base. 2. Three papilL-e form a vallate triangle. 3. The 

 lateral organs consist of fissures and laminae. 4. The sublingua 

 is a flat horny plate with a strong median ridge and a denticu- 

 lated apex bound down to the under surface of the tongue 

 (text-fig. 58, C). 5. The two forwardly-directed glandular 

 processes are stouter and relatively shorter. 



Pseudcchirus peregrimcs. 



The parallel- sided tongue has the following dimensions: — 

 Total length 4-2 cm. ; length of the oral part 37 cm. ; length 

 of the pharyngeal part -5 cm.; width between the lingual attach- 

 ments of the palato-glossal folds '4 cm. 



The PapiUce. — Three circular vallate papdlce form an equilateral 

 triangle with the apex behind ; the basal papillfe are prominent, 

 but the apical one is strongly retracted. 



The fungiform papilla}, which are small and few in number, 

 form a dorsal bounding zone, but they have no definite arrange- 

 ment in transverse rows and clusters; they are surrounded by 

 sharp conical paiMlce, which form transverse rows almost up to 

 the apex of the tongue. Only conical papillje are pi'esent on the 

 ventral bounding papillary zone. 



No orifices of ducts and glands are seen on the base of the 

 tongue. 



The Lateral Organs (text-fig. 58, K). — On each lateral border 

 of the tongue there is a row of circular elevations with central 

 slit-like orifices, so they are not quite similar in appearance 

 to those of Phascolarctos. The slits I'un upwards and backwards. 

 Each organ consists of six areas. Ou the surrounding mucosa 

 there are many nodules and papilhe. 



The Sublingua (text-fig. 58, ]j). — The most pronounced feature 

 of the tongue is the large, soft sublingua. It is firnil}^ bound 

 to the under surface of the apex, as in all Marsupialia in which 

 it is complete, but its under surface is deeply fissured and 

 separated by a deep gap fi-om the tongue (text -fig. 58, D and N). 

 Running backwards in ihe mid line is a strongly-developed 

 median crest, which is bounded behind by a fissure. 



There are great differences, therefore, between the lateral 

 organs, vential surfaces, and vertical sections of the tongues of 

 these three species, as seen in text- fig. 58, B-D and I-N, The 

 essential diflerences between the sublingupe of the Marsupialia 

 and Primates lie in the apices — in the former the apex is fixed 

 to, but in the latter it is free from, the under surface of the 

 -tongue, 



