of Lepus Americanus. 279 



wall of the trench are arranged in a girdle of four or live tiers. 

 From horizontal sections I estimated the average number of 

 bulbs in a tier of the papilla at sixty. If we allow for five 

 tiers, we shall have three hundred bulbs for each papilla. The 

 average number of bulbs present in a tier of the outer wall of 

 the trench appears to be about seventy-five, which, allowing 

 for four tiers, would give three hundred bulbs for this region. 

 The bulbs, as usual, vary in size and shape. The mean length 

 is 0-05 l mm and the mean breadth O033 mra . Most of the bulbs 

 have a fairly well-developed neck, and in many of them the 

 peripheral ends of the sensory cells project for some distance 

 beyond the gustatory pore. The peripheral or supporting cells 

 are elongated, slightly flattened structures, with an oval nu- 

 cleus, containing several nucleoli, situated usually in their 

 lower half. The outer end of the cells is more or less pointed, 

 while their basal pole is generally slightly rounded, though it 

 may be notched or even branched.* The sensory or taste-cells 

 are fusiform, highly refractive elements, and consist of an 

 elliptical-shaped nucleated enlargement, usually placed near the 

 middle of the cell, and two processes. The peripheral process, 

 broader than the central and quite straight, passes to the apex 

 of the bulb, where it frequently terminates in a delicate hairlike 

 projection. In other cells the apex of the peripheral process is 

 truncated, but bears no cilium. The central process, more 

 slender than the peripheral, and occasionally slightly varicose, 

 sometimes divides below the nucleus into two or more branches, 

 but more commonly it ends in a somewhat pointed extremity. 



The circumvallate papilla is well supplied with nerves. 

 Medullated and non-medullated fibers of the glosso-pharyngeus 

 enter the papilla at its base, and ramify in all directions. In 

 the mucosa directly beneath the bulb region, the finer branches 

 form a delicate network. In chloride of gold preparations this 

 subepithelial network is beautifully shown, the fibers of Remak 

 and small ganglia, which are scattered through the membran- 

 ous stroma, being stained deep violet or black. A portion of 

 the terminal fibrils of the plexus enter the bulbs at their base, 

 probably more than are represented by the sum of the taste- 

 cells, while others pass between them and end freely in the 

 epithelium or form an intra-epithelial network. 



The papillae foliatce. — These papillae measure 5 mm in length 

 and 2*7 mm in breadth. Each papilla consists of thirteen or 

 fourteen folds, most of which bear bulbs on their lateral area. 

 The folds are separated by narrow furrows, slightly dilated at 



* Hermann describes three kinds of supporting cells in the taste-bulb of the rab- 

 bit. First, the outer or "pillar cells," which constitute the true supporting ele- 

 ment of the bulb. Second, the inner supporting cells, which resemble the ''staff 

 cells" of Schwalbe and heretofore supposed to be sensory in function; and, third, 

 "basal cells" which he regards as compensating cells for the bulbs. 



