MAMMALS. 599 



attached. This apparatus consists of a transverse middle piece 

 (basis), uneven and convex in front, mostly excavated behind, and 

 usually of two pairs of lateral pieces, the so-named horns, of which 

 the posterior pair in the rats and some other rodents, and in the 

 graminivorous cetaceans is absent. The anterior horns (in man the 

 smallest, cornua minora) are always connected with the temporal 

 bone by cartilages or ligaments 1 . Here are situated in most mam- 

 mals two or three long, sometimes round, sometimes flat bones 

 (ossa styloidea), whilst in man a stylo'id process in connexion 

 with the temporal bone forms the upper part of the junction. The 

 posterior horns (cornua majora) extend backwards and from each 

 other, and are united by ligaments with the thyroid cartilage of the 

 larynx. In Mycetes (Simia seniculus) the basis expands to form a 

 bony vesicle. In the horse, from the anterior part of the arch 

 formed by the middle piece a stiliform process extends, which 

 penetrates the root of the tongue. Different muscles, which run 

 from the sternum, the scapula, the temporal bone, and the lower 

 jaw to the tongue-bone, move it and the tongue with it. Three 

 nerves are distributed to the tongue. The hypoglossal nerve is a 

 motor nerve, and supplies principally the muscles of the tongue ; 

 the glossopharyngeal nerve, common to the tongue and pharynx, 

 goes partly to the posterior portion of the tongue, and sends 

 branches to the papillae seated there, where chiefly the peculiar im- 

 pression of taste seems to be produced; the nerve of feeling of the 

 tongue is the lingual nerve, which arises from the third branch of 

 the fifth pair 2 . The lingual papillae are divided into filiform, 

 conical, obtuse (papilla fang if ormes) and stemmed (papillce vallat&), 

 the last of which are surrounded by a circular groovfc, and"are_larger 

 than the others ; they occur upon the posterior part of the tongue 

 alone ; their number is always small, and their arrangement dif- 

 fers in different genera of mammals. In some, as for example the 

 genus Felis, the conical papillae are covered by a horny investment. 

 The olfactory organ differs from that of other vertebrates both 

 in the cribriform lamina of the ethmoid, of which the apertures 



1 See note, p. 572. 



3 According to PANIZZA the nervus glossopharyngeus is a nerve of taste, the 

 nervus lingualis exclusively a nerve of feeling; see also STANNIUS in MUELLER'S 

 Archiv, 1848, s. 132 138. MUELLER and others, on the contrary, are of opinion 

 that the last-named nerve, although chiefly serving for feeling and touch, includes also 

 nervous filaments for taste. 



