TONGUE OF PERAMELES NASUTA. 75 



probably need the fresh tissue to trace the actual union. The 

 connective- tissue matrix, in which these fibres ramify, is less 

 dense than the mucous membrane of the organ generally, 

 although derived from the latter. This mucous membrane is 

 peculiarly firm and tendinous in appearance, with its fibres 

 arranged transversely to the long axis of the organ and con- 

 taining many interfascular spaces. Striated muscle fibres 

 appear to terminate very abruptly in it. The ganglion and 

 nervous elements are shown in fig, 2, which is taken vertically 

 through the base of the papilla. 



The taste bulbs of the circumvallate papillae are fairly 

 numerous. They are arranged in a zone of seven or eight 

 tiers, exactly filling up the overhanging side of the papilla. The 

 calculation of the number of bulbs in a tier from horizontal 

 sections cannot be very exact. In one semicircle towards the 

 upper part I counted fifty bulbs ; in the lowest there seem to 

 be not less than forty, although here they are somewhat larger. 

 Thus, allowing the mean, ninety in each tier, and allowing 

 for eight tiers, the number of bulbs in each of the three 

 papillae becomes 720. The length of the bulbs appears to be 

 about "07 mm., but the lower are always larger, and the size is 

 somewhat irregular throughout. Their shape is often a per- 

 fect oval, but sometimes rather like that of a peg-top without 

 the spike, for there is hardly any neck, but in longitudinal 

 section the sides seem to meet almost at the surface of the 

 epithelium in a blunt point. The only representative of a 

 neck is the gustatory pore itself, which perforates a very thin 

 apparently homegeneous superficial layer, probably formed by 

 coalesced epithelial cells of the surface (see fig. 2). This 

 layer is also seen covering other parts of the tongue, and is 

 cornified, as it stains yellow in picrocarmine. The perfora- 

 tion of this thin layer is very often seen both in horizontal and 

 vertical sections. In some cases there was a distinct protru- 

 sion through the gustatory pore, but anything like a circlet of 

 hair-like processes projecting from it could not be identified. 

 The cells do not appear to be collected together into a distinct 

 basal pole, although they most distinctly converge at the apex. 



