OP THE TONGUES OF THE MAMMALIA. 



147 



from the pharyngeal division. The former is covered with 

 papillae in all forms except Cystophora prohoscidea, and the 

 latter is folded and covered with orifices of glands and pits, as 

 in the Cetacea. 



The circuvivallate papillce are the chief gustatory organs in 

 Trichechus rosmarus and Cystophora prohoscidea, which have no 

 lateral organs. The}' are sometimes absent as well, so the gusta- 

 tory function is poor or absent in some Pinnipedia. The 

 following table shows the arrangement of the papillae and lateral 

 organs : — 



Species. Circumvallate papillae. Lateral organs. 



Otaria calif or ni ana Absent. Absent. 



„ gillespii „ „ 



Trichechus rosmarus 7 in a V. „ 



Salichoerus gryplius Absent. „ 



FJioca vitulina 5 in a V. Well marked. 



10-12 in a V. 



„ „ 3 in a triangle. „ „ 



„ „ 8-9ina V. „ „ 



Cystophora cristata Absent. „ ,, 



„ prohoscidea 8 in a V. Absent. 



It is, therefore, evident that gustatory organs attain their 

 greatest development in Phoca vitulina, and they are poorest in 

 Otaria californiana, 0. gillespii and Halichoerus gryphus. The 

 conditions are intermediate in Trichechus and Cystophora. 



Fungiform Papillce : — These are numerou.s, scanty or absent ; 

 and when many are present they are thickly clustered on the 

 centre or sides of the dorsum, or spread all over it. They are 

 hemispherical or pedunculated, and the surfaces are smooth or 

 gianular. 



Papillse are absent in Halichoerus gryphus. They are numerous, 

 especially on the centre of the oral part of the dorsum, in Cysto- 

 phora cristata, but they are aggregated around the edges of the 

 dorsum in Trichechus 7'osmarus. In Otaria californiana they are 

 scanty, they stretch right across the dorsum, and they have the 

 usual arrangement. In Phoca vitulina the usual mammalian 

 arrangement is present. In the Cetacea fungiform papillae are 

 absent. 



Conical pap>illce are absent in Trichechus rosmarus and Cysto- 

 phora prohoscidea, but they are present in all other forms. And 

 they have their usual arz-angement in clusters and rows on the 

 oral part of the dorsum. They also increase in size in the usual 

 manner from before backwards and without inwards. The 

 pharyngeal part is folded and devoid of papillse standing up from 

 the surface in Cystophora, Phoca, and Halichoerus, but large 



10* 



