ORGAN OF TASTE IN MAMMALIA. 



199 



rather large, proportionally, in the Aye-aye, becoming more so 

 toward the fauces. The fossulate papil laeform a transverse pair. 

 In Galagos and most other Lemuridce there are three fossulate 

 papilla?, in a triangle, with the apex backward. 1 Obtuse or 

 fungiform papilla? are interspersed with the conical kind in 

 Lemur proper. The tip is sharp-edged in Lemur and Microcebus, 

 round and obtuse in Galago and Aye-aye. 



In some of the Platyrhines the tongue is long, slender, and 

 somewhat pointed, e.g., Callithrix : in which the fossulate papilla? 

 are three in number, with the apex of the triangle backward. 

 The 'sublingua'is rudimental or obsolete in these and in catarhine 

 Quadrumana, in which the tongue gains in thickness and depth : 

 the fossulate papilla? continue to be three in number, but the 

 general structure of the tongue closely resembles that in Man. 



The human tongue, fig. 141, mainly differs from that in Quad- 

 rumana in being, so to speak, less massive, less deep relatively 

 to its length and breadth, with a greater proportion of its 

 margin free, and for a greater extent. It is the most perfect of 

 all tongues in its gustative and other sensibilities, and especially 

 in the rapidity, freedom, and variety of its movements ; whence 

 its applicability to the numerous exigencies of articulate speech, 

 as- well as to prehension, mastication, insalivation and deglutition 

 of alimentary substances. 



Of the muscles moving the tongue some, e.g. ' stylohyoid : ' 

 ' digastricus,' mylohyoid,' ( genio- 

 hyoid,' 6 sternohyoid,' act upon it 

 through the medium of the hy- 

 oidean arch : others, e.g. ( stylo- 

 glossus,' ( genioglossus,' ' hypo- 

 glossus,' f palatoglossus,' arising 

 from extrinsic points pass or are 

 inserted into the tongue's sub- 

 stance : a third class of fibres 

 mainly constitute that substance 

 in which they both begin and end, 

 and are called the , ( intrinsic 

 muscles,' and collectively ' lin- 

 guales.' In the transverse sec- 

 tion, fig. 145, the genioglossi, d, are seen decussating vertically 

 with the central intrinsic fibres, c: these are nominally dis- 

 tinguishable from the ' peripheral mass ' of these fibres, b, owing 

 to their greater number and more compact arrangement at this 



1 LXXXV". pi. 8, fig- 7, 



145 



Transverse section of Human tonffno, at 

 the fore part of ;lie frwuum CCXL. 



