No. 2.] ON THE GUSTATORY ORGANS. 1 77 



the mucosa. Covering the papilla is a dense mass of stratified 

 epithelium. No separation of the epithelium into distinct lay- 

 ers was possible in my sections. The secondary papillae or 

 processes are eight to twelve in number. At the lower part of 

 the papilla they are grouped near the centre of the main up- 

 growth. At higher levels they form an incomplete ring round 

 the edge, leaving a horseshoe-shaped space within. The free 

 ends of the secondary papillae are very short, and completely 

 cornified. They terminate in sharply pointed spines, the apices 

 of which are directed inwards and slightly backwards. The 

 secondary papillae of Pteropus separate from the main papillary 

 body at a very much higher level than in the Marsupialia, and 

 their free portion is consequently much shorter. The termi- 

 nal hooks are also relatively stouter in the former than in the 

 latter, and more completely cornified. The papillae are largest 

 and fullest developed along the central portion of the dorsum. 

 Towards the lateral border and tip they lose the ring of second- 

 ary processes, the latter being replaced by one or more short 

 spines. 



Gustatory Structures. 



The Circiimvallate Papill(E. — These papillse measure 1.25 mm. 

 transversely, and are 0.60 mm. in height. Their summits are 

 convex and slightly verrucose, and overtop the adjacent lingual 

 area. The trenches are rather narrow, but not deep. Serous 

 glands are very abundant within the papillae and beneath and 

 around them. The ducts are numerous and usually open at the 

 bottom of the trenches. Those of the intrapapillary glands 

 traverse the epithelium of the lateral wall, and open at a higher 

 level. The bulbs of this taste area occupy the overhanging wall 

 of the papilla, but are not entirely confined to it. They occur 

 in the epithelium of the outer wall of the trench, and isolated 

 ones are present on the lateral slopes of the upper surface of 

 the papilla. Those of the overhanging wall are quite closely 

 packed, and are disposed in a zone of eight to ten tiers. On 

 the outer wall their arrangement is less regular. In a well- 

 filled tier of the papilla there appear to be at least eighty bulbs. 

 In a transverse section through the lower part of the outer wall 

 I counted one hundred and seventy-five bulbs ; the section, 

 however, included parts of several tiers. The bulbs are long 



