ON THE ANATOMY OF THE TONGUES OF THE MAMMALIA. 115 



10. The Comparative Anatomy of the Tongues of the 

 Mammalia. — I. General Description of the Tongue. 

 By C. F. SoNNTAG, M.D., Ch.B., F.Z.S., Anatomist to 

 the Society. 



[Received Jaiiuai-y 22, 1920 : Read March 16, 1920.] 

 (Text-figm-es 6-17.) 



A considerable body of literature dealing with the development 

 aud histology of the tongue has appeared in recent years, and a 

 number of individual tongues and groups have been described. 

 No one has, however, taken the various structui-es and shown 

 how they vary in different animals in exactly the same manner as 

 I have described here. It is the object of my series of papers to 

 fill this gap, and show how the tongue is of value for purposes 

 of classification. In this paper I have indicated the different 

 directions in which the various structui'es can be modified, and I 

 have defined the terms used in the succeeding ones. 



The tongue is a muscular organ enveloped in mucous membrane 

 except at the ba,se and the posterior pai-t of the inferior surface 

 where the muscles, nerves, vessels, and lymphatics enter and 

 leave it. On the dorsum and inferior surface the mucosa differs, 

 being firmly adherent in the foruier situation and loosely 

 attached to the subjacent tissues in the latter. On the dorsum, 

 lateral border, and, isi most cases, on a hounding zone of the 

 inferior surface it is covered with innumerable papillae which 

 make these parts rough to the touch. The roughness reaches its 

 greatest degree of development in the Felidte, in which the 

 individual papillse stick into the finger like so many pins. In 

 the non-papillary part of the inferior surface, the mucosa is 

 smooth, but it may have ridges and fissures. These do not, 

 however, affect the smoothness. 



Shape. 



Mammalian tongues differ greatly in shape, being oval, conical, 

 spatulate, triangidar, or vermiform, but these forms are not of 

 any value for comparative purposes. 



Size. 



Two sets of measurements must be made — the greatest width, 

 and the length — and the latter is divided into two — the lengths 

 of the oral and pharyngeal parts. In most cases the greatest 

 width is situated at the attachments of the anterior faucial 

 pillars to the dorsum, but in spatulate tongues it may lie farther 

 forwards. 



The length is measured from the apex to the mid point of the 

 glosso-epiglottidean fold. The oral part extends from the apex 

 to the median circumvallate papilla, when there is one, or to 



