16 



MINOT ON THE TONGUE 



Cut 5. Mimus polyglotius ; section 

 throuc!;li the base of the tongue (Fig- 3, 

 line 1) By. hyoid; gV, dorsal, gV, 

 ventral, glands; K, VI, longitudinal 

 muscles ; V, blood vessel. 29 diam. 



basal portion, at the point where the cornu are just separating from the body of the 

 hyoid, the- three forming a triangular central bone, Hy, which contains a number 



of medullary cavities, filled with a peculiar tissue, which oc- 

 curs also in the other bones of the hyoidean apparatus. This 

 tissue consists of numerous large, clear spaces, separated from 

 one another by thin partitions — 1 think each space must be 

 a large vesicular cell, for I can occasionally see a small nucleus 

 lying against one of the partitions.. The tissue is permeated 

 by numerous blood-vessels, which can be easily seen passing 

 in and out among the clear spaces (cells ?) of the tissue. The 

 epithelium is quite thick, with a well-developed corneous 

 layer, and is thicker on the under, than on the upper, 

 side. The break below is an accidental injury. In this 

 part of the tongue there are only longitudinal muscles, the 

 large I' above, and the small l" below. Under the dorsal epithelium is a layer of 

 conglobate glands, gV, which open by short ducts directly upon the upper surface. 

 These glands, which are not mentioned by previous observers, are probably homol- 

 ogous with the glands on the back of the mammalian tongue. Laterally and ventrally, 

 are two long and tubular glands, gl ", with follicular walls. They are oval in 

 section, have a rather small lumen and a fibrous tunica propria, which sends up partitions 

 between the folHcles, which make the principal part of the walls of the glands. The fol- 

 licles are narrowest at their mouth, and widen towards the base, the height of the lining 

 cylinder epithelium increasing, but there is no marked separation of duct and gland m 

 the follicles. I first noticed these glands in sections, and cannot say where they open. 

 The epithelium of the tongue is moderately thick, and has a well developed corneous 

 layer, in which all trace of cellular structure has disappeared. Picrocarmine dyes the 

 corneous layer bright yellow, the mucous layer red. A large blood vessel V, lies under 

 the hyoid bone. 



A section through the back part of the free flattened portion of the tongue, through 

 the m. transversus linguae, is figured in cut 6. The section is, roughly speaking, triangu- 

 lar, the broadest side corresponding to the upper sur- 

 face of the tongue. The epithelium is very much 

 thickened above, both the corneous and mucous lay- 

 ers having increased ; the latter sends down rounded 

 papillae into the cutis. At the sides, the epithelimn 

 rapidly diminishes in height, becoming quite thin 

 underneath, where the corneous layer is not difier- 

 entiated. In the centre is the section of the basihyal. 



Cut. 6. Mimus pohgUttm. Transverse seel ion of JJy ^nd at the sidcS in the SUperior aUQ-leS, the entO- 



touguo. Un, liyoid ; Am, entoglossum ; Tr, transverse .J ' jr O ' 



muscle. (ciT line 2, Fig. 3. B). x 29 diam. glossi, Ml. Prom thcsc last ariscs the powerful trans- 



verse muscle, running from one entoglossum to the other ; its fibres curve downwards to 

 pass under the hyoid, with which it has no connection. The remainder of the section is 

 occupied by connective and vascular tissue. The free flattened portion of the tongue con- 

 tain no glands. 



