_73 



The taste bulbs of this area are very numerous, and are usually 

 in contact by their edges or overlap one another. They are placed 

 around the sides in a zone of 25 or 30 tiers, the uppermost tier being 

 often well up towards the summit of the papilla. Bulbs are likewise 

 occasionally present in the lower part of the outer wall of the trench. 

 The bulbs vary greatly in size, but their average length is about 

 0,075 mm, and their greatest transverse diameter 0,035 mm. The 

 smallest occur in the epithelium covering the broad expanse of under 

 surface, which this papilla possesses, and which is very like that 

 already described by me in the papilla circumvallata of Mephitis*). 

 I have counted in this region sixty-five bulbs, but they were all quite 

 small. It is a difficult matter to estimate very accurately the number 

 of bulbs in the papilla circumvallata of the pig; but judging from hori- 

 zontal and vertical sections there must be at least 6000 bulbs in each 

 of the two papillae. 



A large number of non-medullated nerve-fibres enter the papilla 

 (being derived from the plexus at its base), from which smaller 

 branches radiate upwards to the top of the papilla and laterally to- 

 wards the basal poles of the bulbs. Large ganglion cells are also 

 present beneath the papilla. 



The Papillae fungiformes. — These papillae are mostly of the 

 usual form. Some of the smaller ones, however, offer a variation from 

 the ordinary type. In these the upper surface is surmounted by fif- 

 teen or twenty cone-shaped papillae, some of which are truncated. 

 At their upper part the epithelium is shghtly cornified. 



The tongue in which the papilla foliata was wanting possessed 

 many papillae fungiformes containing taste bulbs. They are usually 

 disposed at the upper part of the papilla, but occur now and then 

 at the sides. I have never yet succeeded in finding them at the base. 

 The largest number visible in a single vertical section of this papilla 

 was seven. In their size, and generally in their shape, these bulbs 

 vary but slightly from those of the circumvallate and foliate areas. 

 Those situated at the upper part of the papilla are placed obliquely 

 to its long axis, their apices being directed upwards and outwards, 

 and sometimes reaching the free surface of the epithelium. The bulbs 

 appear to be entirely epithelial in position; in a single instance only 

 did the base of a bulb seem to touch the mucosa. 



1) Quart. Journ. of Micr. Sei., vol. XXVIII, 1887, p. 158, pi. XI, 

 figs. 2 and 3. 



