TONGUE OF PERAMELES NASUTA. 73 



is prolonged upwards very nearly to the level of the surface of 

 the papilla, and as this is rather above the level of the tongue 

 the papilla is surrounded by a slight ridge. The trench is 

 very narrow, and its depth and relation to the shape of the 

 papilla is shown in fig. 1, which is magnified 245 diameters. 

 Thus, in shape this papilla is peculiarly specialised in the 

 way of protection; its minute structure will also be found to 

 be highly specialised in many points. Glands are very 

 abundant within the bodies of the papillae, betAveen the three 

 papillae, and for a considerable distance around them. They 

 are almost entirely of the granular " serous " type, which 

 Klein points out as always accompanying taste bulbs. Their 

 structure is exactly as described by Klein. Their ducts open 

 into the trench, especially in its deeper part, and are very 

 numerous. In one horizontal section I counted twenty-six 

 ducts, probably all separate, and at a lower level I calculated 

 that there must have been at least forty at one horizon, while 

 the bottom of the trench is completely surrounded by thickly 

 crowded gland-ducts radiating inwards (see figs. 1 and 2 for 

 vertical sections). The body of the papilla, as usual, bears 

 secondary papillae on its upper part, the depressions between 

 which are filled up to one level by the epithelium. 



The most remarkable structure, and as far as I am aware 

 one hitherto undescribed, is a large and distinct ganglion in 

 the form of a thick axial column making up a great part of 

 the bulk of the papillary body. It is surrounded by a clearly 

 defined connective-tissue capsule, which enters and supports 

 the nervous elements. Above, the ganglion breaks up into 

 branches, which stream outwards towards the sloping side of the 

 papilla containing the taste-bulbs. The gradual collection of 

 the scattered branches above and to the sides into the dense 

 and compact ganglion centrally and below is especially well 

 seen in successive horizontal sections. The nerve-fibres appear 

 to be almost entirely non-meduUated, but they possess a distinct 

 sheath of Schwann. Among the nerve-fibres occur primitive 

 nerve-fibrils. The nerve-cells are few in number, very large 

 and distinct (they are indicated even in the lowly magnified 



