442 



SPECIAL HISTOLOGY. 



its root, forming a long, moderately broad, fleshy mass, which, however, 

 is anything but compact. The genio-glossi, in fact, when they have 

 entered the tongue, exchange a few bundles here and there, along the 

 lower edge of the septum, and then break up on each side into a great 

 number of lamellce, which lie one behind the other, separated by small 

 interspaces, in which are the transverse muscular fibres of the tongue ; 

 the lamellce are, for the most part, perpendicular, but some curve for- 

 wards and backwards, towards the dorsum of the tongue. 



The fibres of the genio-glossus, thus separated into distinct lamellce, 

 which have, on the average, a thickness of 0-06-O14 of a line, extend 

 as far as the septum, and then gradually take a new arrangement, so as 

 to be directed from behind forwards. For whilst, previously, the genio- 

 glossi were broken up into transverse lamellce, by the bands of the 



Fig. 169. 



/ 



transversus, they are now separated longitudinally by the interposition 

 of the bundles of the superior longitudinal muscle of the tongue, between 

 their fibres. These perpendicular longitudinal lamellce are very distinct 

 in the two anterior thirds of the tongue, less so in the vicinity of the 

 papillce circumvallatce, where, especially in the middle of the tongue, 

 the genio-glossus passes, in more isolated bundles to the mucous mem- 

 brane ; in the root of the tongue, finally, they cannot be demonstrated 

 at all. The genio-glossus ends upon the upper surface of the tongue, 

 in such a manner, that its primitive bundles, immediately beneath the 

 mucous membrane, are continuous, in groups, with little tendinous 

 streaks of connective tissue, which then partly become lost in the 



FIG. 1G9. Longitudinal section of the human tongue, natural size; the outlines after 

 Arnold Icon. org. (sens.) ; g.h, genio-hyoideus : A, hyoid bone ; g, genio-glossus ; g\ glosso-epi- 

 glotticus ; tr, transversus lingua; l.s,longiludinalis superior; e, epiglottis ; m, maxilla inferior; 

 d, incisor tooth ; o, orbicularis oris ; l.m, levator menti 1. glandula labialis ; folliculi linguales ; 

 gl, glandula linguales cum dudibus. 



