162 SPECIAL HISTOLOGY. 



medium and thyreo-arytcenoidea inferiora contain a preponder- 

 ance of elastic tissue and are of a yellow colour ; whilst others, 

 such as the thyreo-aryttenoidea superior a, hyo- and thyreo- 

 epiglottica, and the membr. hyo-thyreoidea, are characterised, 

 at all events, by the great abundance of that element which 

 they present. The elastic fibres of the laryngeal ligaments are 

 of the finer sort, scarcely exceeding 0*001'", and are united 

 in the usual manner into a very close elastic network ; which, 

 however, even where it is apparently most unmixed, contains 

 some connective tissue. The muscles of the larynx are all 

 transversely striated with fibres of 001 6 — 0024'", and present 

 the same structure as those of the trunk. They arise from the 

 cartilages, and are inserted into them, and also into their 

 elastic ligaments; the latter being the case with the thyreo- 

 arytanoideus, which is for the most part lost on the concave 

 side of the vocal ligaments. 



The mucous membrane of the larynx, the continuation of that 

 of the throat and mouth, is smooth, whitish red, and con- 

 nected with the subjacent parts by the ordinary, in some places 

 abundant submucous connective tissue. Except in the glottis, 

 the mucous membrane, covered only by a ciliated epithelium, 

 and presenting no papilla, abounds in finer elastic fibrous net- 

 works, particularly in its deeper portions ; whilst the innermost 

 layer, .0*03 — 0-04"' thick, consists principally of connective 

 tissue, and ceases in an inseparable, homogeneous border of 

 0004'". The ciliated epithelium, in the adult, commences at 

 the base of the epiglottis and, above the upper vocal ligaments, 

 is composed of several laminae (vide § 21), on the whole 

 0*024 — 0*04'" thick; with the exception of the vocal liga- 

 ments, which, as was discovered by H. Rheiner and I can 

 confirm, have a squamose epithelium, it lines the rest of the 

 larynx throughout. The proper ciliated cylinders 0*015 — 

 0*02"' long, and 00025 — 0*004'" broad in the mean, with 

 elongated round nuclei of 0*003 — 0*0045'", and occasionally 

 with a few fat-granules, are mostly much acuminated, fre- 

 quently even prolonged into slender filaments, which may 

 attain such a length that the entire cell may equal 0*024 — 

 0-027"'. - The cilia are fine, transparent, soft processes of the 

 cell-membrane, 0*0016 — 0*0022 long, which arise from it with 

 a rather broader basis, and terminate in a pointed extremity. 



