584 THE MICROSCOPE. 



belong the Salmon, Herring, Eel, Carp, Blenny, and the 

 majority of our edible fishes; their scales are circular and 

 laminated. The scales of the Eel tribe are of an oval 

 figure, and are among the most remarkable that can be 

 selected for microscopic examination. To procure them, a 

 sharp knife must be passed beneath the epidermal layer, 

 and a portion of it raised, in a similar manner as directed 

 for tearing off the cuticle from plants : after a few trials 

 some will be detached. They are of an oval figure, rather 

 softer than the scales of other fishes, and in some parts of 

 the skin do not form a continuous layer. When the skin 

 has been stripped off, previous to the fish being cooked, the 

 scales can be obtained from the under surface, with a knife 

 or pair of forceps. The scales of the viviparous Blenny are 

 of a circular figure, situated under the epidermal layer ; 

 they were described by Mr. Yarrell as mucous glands, from 

 their figure and small number. The surface of the skin of 

 this fish, when fresh, appears to be covered with follicles ; 



Fig. 324. The Stickleback. 



if, however, a portion is scraped off, it will be seen to be 

 a mass of delicate circular scales. A piece of the skin, 

 when dried, exhibits the scales to great advantage, and, 

 like those of the Eel, are beautiful objects for polarised 

 light. The prismatic colours exhibited by fish are said to 

 be due to the presence of fatty matter in the skin ; but 

 the beautiful metallic tints displayed by so many of them 

 are rather due to the numerous microscopic plates, or 

 scales, distributed over the surface of the skin. 



Having thus brought our brief examination of a few of 

 the more important structures of the animal economy to 

 a close, it only remains for us to express a hope that it 

 will be found to smooth the way, or in some degree assist 

 the investigations of the student to a better and more 

 general survey of the whole fabric. Such a survey will 



