•883.] TONGUES OF THE MARSUPIALS. 607 



granular cells which in many other Marsupial tongues {Perameles 

 &c.) form the transition into the upper corneous layer are slightly 

 marked here. It is very likely that the transition described 

 through the complex layers takes the place of the other method. 

 There are, however, some finely granular cells in layer (4). The 

 complex epithelium ends at the entrance into the involution for the 

 circumvallate papillae in the same way as at the mouths of the 

 lateral organ (see fig. xxxi. Plate LV.). 



B. The Filiform Papillce, forming the limits of the papillate 

 surface above and behind the lateral organ, are probably tactile in 

 function. They are of small size for so large a tongue. They are 

 similar to those described in Phalangista. 



Thus in many points connected with the tongue, Hahnaturus is 

 the most primitive Marsupial yet examined — in the very primitive 

 lateral organ, in the extremely protected circumvallate papillae with 

 bulbs nearly covering them, and in the irregular coronate papillge 

 and the existence of scattered hair-like papillae between the latter, 

 with no apparent tendency towards coalescence into rings. 



The Tongue of Macropus melanops. 



This tongue had been kept in spirit, and the tissues were not in a 

 condition for minute examination ; but many points of interest could 

 be ascertained. The pieces of the tongue from which I intended 

 to make sections I placed in spirit, gradually increasing the strength 

 until they were finally placed in absolute alcohol, and were cut after 

 remaining some little time in this fluid. 



General description. — The ajipearance of the tongue from above 

 is shown in fig. vi. Plate LIV. (half natural size). Tiiis organ is 

 evidently closely related to that of Hahnaturus. The circumvallate 

 papillae are arranged as usual, the posterior angle being exceptionally 

 obtuse, although not to the same extent as in Halmaturus. As in 

 the latter animal, the depressions leading into the cavities containing 

 the papillae are alone visible from the surface and are very incon- 

 spicuous. The lateral organ (fig. vii. Plate LIV., natural size) also 

 resembles that of Halmaturus; but the mound-like elevations are 

 arranged in a regular curve, and the depressions have more of the 

 normal appearance. Independent mucous glands cannot be seen 

 in this specimen, but they may be present ; filiform papillae are 

 arranged above the lateral organ. The fungiform papillae are very 

 abundant all along and just above the edge where the papillate 

 joins the non-papillate surface. At the tip the junction is beneath 

 the tongue and forms a line parallel with the contour (see fig. v. 

 Plate LIV., natural size). On this papillate surface beneath the tip 

 fungiform papillae are extremely abundant, and many of them are 

 unusually large. There is little doubt that papillae in this position 

 are tactile. The free part of the tongue is about (iO mm. long, and 

 there is a raphe detectable for about SO mm. from the tip back- 

 wards. The inferior median ridge is low and wide, and the lateral 

 grooves shallow (see fis. v. Plate LIV.). 



40* 



