OF THE TONGUES OF THE MAMMALIA. 135 



The patch may be completely surrounded by a zone of small 

 papillae, or it may extend laterally till it coveis the whole width 

 of the tongue. The histology and chemistry of the horny 

 epithelial sheaths of the papillee have already been described by 

 Severin (28), Klein and Verson (17), Csokor(7), Podwisotsky (25), 

 and Ranviei* (23). The ventral papillary zone may be composed 

 of small conical papillae alone, or of both conical and fungiform 

 types. 



Family Felidce : — In all forms the spinous patch is surrounded 

 by a zone of small papillae, but it vaiies in size, and in the 

 prominence of its papillae. The points of the papillae are directed 

 backwards, and are straight or recurved to a variable degree ; 

 but those of the papillae on the encircling zone face backwards 

 and inwards. The lateral papillae may increase or decrease from 

 before backwards, but the papillae spinosae increase in size from 

 without inwards. 



In all Felidae except F. leo and F. onca the conical papillae 

 extend back to the epiglottis, but in these species the most 

 posterior papillae are separated from the epiglottis by a smooth 

 mucous surface. The conical papillae on the pharyngeal part may 

 be smaller or larger than those on the oral part of the dorsum. 



The characters to which special attention must be paid are : — 



1. The extent of the small band of conical papillae encircling 

 the patch of papillae spinosae, and tlie relative quantities of fungi- 

 form papillae situated on it. 



2. The posterior limit of the spinous patch, and the distance 

 between the anterior extremity of the pa,tch and the apex of the 

 tongue. 



3. The characters of the papillae spinosae, particularly the shape 

 of their spines and their closeness or separateness. 



4. Characters of the conical papillae behind the spinous patch. 



5. Presence or absence of a row of papillae clavatae in the region 

 of the lateral organ on each side. 



6. The relative sizes of the conical papillae on the oral and 

 pharyngeal parts of the dorsum. 



7. Character of the ventral papillary zone. 



In Felis leo (text-fig. 18) the small papillary zone girdling the 

 spinous patch extends back along the anterior third of the tongue. 

 The spinous patch begins close to the apex of the tongue, but 

 does not reach the middle of the oral part of the dorsum. The 

 papillae spinosae have sharp, recurved, closely-set points so their 

 bases are not much exposed. Behind the patch the conical 

 papillae form a central band of small ones and two lateral tracts 

 of large ones. No clavate papillae are present, and the papillae on 

 the pharyngeal part of the dorsum are small. In F. tigris (text- 

 fig. 18) the conditions are in general similar to those in the lion, 

 but their development is not so great. The papillae spinosae have 

 recurved, but not very prominent points, but the conical papillae 

 on the pharyngeal part of the tongue are prominent. Fungiform 



