134 ORGANS OF OFFENCE AND DEFENCE. 



means close, the pigment is often pearly, and the 

 epidermis, if it be not entirely deficient, often very 

 slender. 



In all its modification of form and accessaries, 

 however, whether by the appearance of strong 

 armour to resist attack, or by mucous and viscid 

 lubrucations to facilitate escape, the skin is the first 

 and most important organ of defence.. And the 

 most remarkable appendage of this integument in 

 fishes is the scales ; they differ from hairs and fea- 

 thers in having no generating bulbs nor have they 

 the same character as the scales in the Edentates, 

 Dasypus, Manis, Chlamyporus, &c., or in reptiles. 

 More or less firmly adhering to the skin, they are 

 shut up free in a species of pouch much flattened, 

 and formed by a pinching up of the rete mucosum 

 and its vascular tissue. To permit their separation 

 and escape, this pouch must be torn. They appear 

 to be produced by the internal surface of this vas- 

 cular pouch, and to become excessively flattened, 

 each composed of horny lines meeting in an apex, 

 and derived from a more or less extended base, ac- 

 cording to the form of the scale, and that is very 

 variable*. 



It is commonly asserted that all fishes have 

 scales but in some they are not discoverable by 

 the eye, and in others they do not appear in the 

 fresh condition of the skin, but only when it has 

 become dry. Under the former description fall the 

 hag (Mixine glutinosa), and the lamprey (Petro- 

 * Op. cit. i. 144. 



