Terminations of tlie Nerve.s in the Tongue of the Chelonia. 3 



columnar cells appear to be wanting. The mucosa is far from dense, 

 and contains many interfascicular spaces. Tt consists of a loosely 

 woven matrix of very fine fibrils of connective tissue, and is faiiiy ridi 

 in nuclei. 



Mucous giands are excessively abundant in the tongue of Testudo. 

 They are not as numerous in the mucosa and submucosa beneath the 

 papillae of the dorsum as in the corresponding regions of tlie sides, 

 but they are still quite plentiful here. At the sides of the tongue 

 they are closely packed and form a belt of varying width, separating 

 the bundles of striated muscle-fibres and epithelium, and filling com- 

 pletely in places the apace between them. Not infrequently in tliis 

 region the glands entirely fill the interior of a papilla, touching the 

 epithelium apparently at every point (see figs. 1 and 2). The papillae 

 of the dorsum are likewise partly occupied by mucous giands, and many 

 isolated ones lie wholly within the epithelium investing their lateral 

 area. The ducts traverse the epithelium obliquely, and open into the 

 interpapillary spaces. The mucous glands may thus be said to form a 

 distinct layer, which very nearly encircles the tongue. At the under 

 part of the organ, where the giands are wanting, the intervening space 

 is filled with bmidles of muscular tissue. The striae of the muscle- 

 fibres^are excessively fine, and require a high power to show them 

 clearly. The mucous cells lining the lumen of the alveoli, are long 

 transparent columnar cells. The nuclei are seen with difficulty, being 

 flattened and compressed in the direction of the membrana propria. 

 At the peripheral part of the cells are peculiar, dark, more or less 

 granular masses, which may possibly be the demilunes of Heidenhain, 

 the crescents of Gianuzzi. In the smaller gland-ducts the longitudinal 

 striation of the epithelium is very beautifully shown. 



Each papilla is supplied with small nerve-fibres which, after pen- 

 etrating the papilla for some distance, finally lose their medullary 

 sheath. The smaller nerve-branches form a plexus in the connective- 

 tissue matrix directly beneath the basal layer of the epithelium. From 

 the subepithelial plexus thus formed vei-y minute fibrils ascend towards 

 the epithelium of the upper area of the papilla. Small branches are 

 given off from the nerve trunks before they reach the level of the 



