1146 



TONGUE. 



surmounted by two cerato-branchlals (c 6) of 

 extreme length and tenuity, which, curving 

 round the bird's occiput and vertex, are 

 inserted by their cartilaginous extremities into 

 a canal in the upper mandible, the orifice of 

 which is placed to the inside of the right nos- 

 tril ; the true hyoid arch is here entirely sup- 

 pressed. And, indeed, birds' tongues are not 

 attached, they are slung ; now, tongues are 

 attached by the osseous or fibrous continuity 

 of the hyoid arch ; they are slung by the loose, 

 unattached hypo- and cerato-branchials ; and 

 accordingly as either of these methods of con- 

 nection with the body is most consistent 

 with the tongue's functions, so the one or the 

 other of these systems of bones preponde- 

 rates. 



In mammalia we find the hyoid apparatus 

 recurring in its original completeness ; the 

 three pieces, the stylo-hyal, epi-hyal, and 

 cerato-hyal, composing the lateral arms of the 

 arch in the fish, have each their representa- 

 tive : the proportion of these parts, the com- 

 pleteness of their ossification, and their anchy- 

 losis, or separateness one from another, are 

 liable to great variety, but either in the bony 

 or ligamentous condition, fused or separate, 

 the parts may be always traced. The cerato- 

 hyals are represented by the lesser cornua ; the 

 stylo-hyals have their homologue in the sty- 

 loid process of the temporal ; and the epi- 

 hyal, or intervening portion of bone, is a cylin- 

 drical ossicle connecting the two : these are 

 seen in their greatest completeness in the true 

 carnivora. In man the epi-hyal is not normally 

 ossified, but remains in a permanently liga- 

 mentous condition, as the stylo-hyoid liga- 

 ment. In some rare instances, this ligament 

 has been ossified, and then the typical condi- 

 tion of the hyoid arch is restored ; two or 

 three of these instances have been recorded 

 and figured by Geoffrey. In fig. 760. E is 

 shown the condition of the hyoid apparatus in 

 the horse ; the stylo-hyals are seen to be very 

 large, and approximate so nearly to the cerato- 

 hyals, that the intervening bone, corresponding 

 to the stylo-hyoid ligament in man, is seen to 

 be a mere pisiform nodule (ep k) ; the hypo- 

 branchials, or posterior cornua (ft ), are of 

 much the same shape as in man, while the 

 basi-hyal projects forwards in a rostrum, to 

 which is attached a glosso-hyal in two pieces 

 (g A). In the ox the condition is much the 

 same as in the horse, but the epi-hyals are 

 longer, and the stylo-hyals shorter. 



I will now briefly advert to the general 

 characters of the tongue itself, as met with in 

 the four classes of Vertebrata, Pisces, Rep- 

 tilia, Aves, and Mammalia. 



Pisces. The tongue in fish is very rudi- 

 mentary ; in some it cannot be said to exist at 

 all ; in others it is a thin, fleshy investment, 

 that barely covers the glosso-hyal bone pro- 

 jecting into the mouth. In the herring (Clupea 

 Harengus\ it seems to be represented by a 

 small muscle passing along the floor of the 

 mouth to be inserted into the symphysis 

 of the lower jaw, to depress and open which 

 seems to be its function. In the cod it is 



round and thick, and seems to act as a sort of 

 cushion. In the conger {Murtena Conger), in 

 which it is very large, it seems to possess a 

 hyo-glossus muscle, which, arising from the 

 inferior portion of the hyoid arch, passes for- 

 ward on either side of the tongue, which, by 

 the action of one of these muscles, can thus 

 have a lateral deflexion imparted to it. The 

 structure of the investments of the tongue is 

 not such as to imply the possession of taste in 

 any degree, or any thing but a very low sensi- 

 bility. In some species, as, for instance, in the 

 sole (Solea vulgarii), the surface is regularly 

 rugose, and might, at first sight, appear to be 

 papillary, but no true papillae are to be met 

 with in any fish's tongue ; their only repre- 

 sentatives are the calcigerous processes, or 

 teeth, with which the tongues of some species 

 are more or less densely set, and which assist 

 in prehension and deglutition. Whether the 

 vascular, erectile tissue, situated on the palate 

 of the Cyprinoids, has any connection with the 

 sense of taste, is doubtful probably not. 



Reptilia. The tongues of Reptilia possess 

 a very wide diversity ; some are immovable, 

 others the most remarkable for their protrac- 

 tility that we find in any organism ; some are 

 long, some so short as to have been described 

 as wanting ; some are broad and thick, some 

 slender ; some present the development of 

 papillae in great perfection, some are quite 

 smooth; the extremes of all these charac- 

 ters we find in the reptiles, and their oppo- 

 site conditions in those the most closely 

 allied. For example, among the Saurians, the 

 tongue of the crocodile is so immovable, as 

 to have been described by Aristotle as want- 

 ing; while the chameleon presents us with 

 the most complete protractility of the organ 

 that the animal kingdom furnishes. I think 

 the ideologists have not a greater strong hold 

 than that furnished them by the tongues of 

 reptilia. Almost the only thing in common 

 that can be assigned to them is this, that pre- 

 hension is their principal function, and that 

 the sense of taste is very subordinate. 



a. Batrachia. All the Batrachia, in their 

 perfect state, feed on living prey*, and in 

 many of them the arrangement of the tongue, 

 to enable them to secure it, is remarkably 

 curious. In the frog, which presents a good 

 example, we see the tongue reversed, as it 

 were, the base or attached end being in front, 

 the apex or free extremity behind : its mus- 

 cular constitution explains this arrangement. 

 It consists essentially of two muscles, a genio- 

 glossus and hyo-glossus, invested by the 

 mucous membrane. The genio-glossus arises 

 from the inferior maxillary symphysis, and, 

 directed backwards towards the throat, spreads 

 out, and, together with its fellow, constitutes 

 the upper of the two muscular strata. The 

 hyoglossi arise from the lower surface of the 

 posterior hyoid cornua, are directed forwards 



* In speaking of the frog Roesel says, " Praedam 

 vix venatur eamdera potius praestolans, nee ullum 

 unquam devorabit insectum motu destitution." Hist. 

 Ranar., p. 16. 



