REPTILES. 229 



Amongst the organs of sense in reptiles that of feeling, or the 

 modification of it as tact, comes in the first place under consideration. 

 The skin of animals is not merely adapted as a covering to protect 

 them from injurious external stimulants, but serves at the same time 

 as a seat for feeling. In this class, however, the skin is generally 

 to be regarded rather as a protective covering, since scales or hard 

 shields render it unfit for feeling. The true skin (corium) is in the 

 greater number very firmly connected to the muscles or bones which 

 are situated beneath it. In the frogs, on the contrary, it forms a 

 loose sac, except only on the head and the extremities of the limbs ; 

 and this sac, which may be inflated, is attached to the subjacent 

 parts, only here and there at the back or near the joints, by filaments 

 of nerves and vessels or fibrous tissue ; a serous fluid, lymph, occu- 

 pies the space between the skin and the muscles below it. The 

 corium in this class is always composed of several layers of fibres 

 (sometimes of very many when its thickness is considerable), which 

 lie close together: and it has been noticed that the direction of the 

 fibres in each of the layers alternates with that of the previous 

 and succeeding layers, making with them nearly a right angle. 

 The casting or moulting of the cuticle is very general also in the 

 naked diplopnoa; in the serpents the external covering of the eye- 

 ball is moulted with the cuticle. In some lizards, in the crocodile, 

 &c., the scales or scutes are ossified. Perhaps by grasping of objects 

 fwith the tail, in certain lizards, or with the whole body, as in 

 serpents, a perception of the form and surface of such objects may 

 be procured. Probably the tongue in some serves as an organ 

 of tact (see above p. 211). 



Taste appears to be feebly developed, for most reptiles gulp their 

 prey very rapidly. TREVIRANUS, indeed, from having observed that 

 frogs, when by chance they have swallowed what is disagreeable to 

 :hem, quickly reject it again, would conclude that they possess the 

 iaculty of distinguishing their food by taste 1 ; but this may be> 

 'egarded, and perhaps with greater truth, as a proof that the stomach 



ympathischen Nervensy stems, Leipzig, 1842, 4to, s. 32, 33, Tab. in. fig. 7; BOJANUS 

 I not. Testud. pp. no 113, Tab. 23, figs. 116, 117; GILTAT Diss. de Nervo sympa- 

 nco, pp. 7596 ; MUELLER Vergl. Neurologic der Myxinoiden, s. 59 63, Tab. rv. 

 gs- 3 4, 5- 



1 Biologic, VI. s. 245. 



