OSTARIOPHYSI 585 



along the lateral line and the back, and the Gold-Fish, a variety 

 of Cyprinus carassius, remarkable for its golden or bright red 

 colour, or its perfect albinism, as well as its monstrous form the 

 Telescope Fish, with enormously projecting eyes, and enlarged, 

 horizontally spread caudal fin.^ This family has also yielded 

 numerous more or less well-established examples of hybridism, 

 congeneric and digeneric, originally described as distinct species, 

 the produce of which is believed to be in some cases fertile for 

 at least one generation. 



The crystalline silvery colouring matter of various Cyprinids 

 is said to have been employed from time immemorial for orna- 

 mental purposes by the Chinese. The well-known and important 

 industry of " Essence Orientale " and artificial pearls, carried on 

 in France and Germany with the scales of the Bleak, was not 

 introduced before the middle of the seventeenth century. 



Fig. 354. — Pond Loach (Misrjurnus fossilis), witli lower view of mouth. J natural size. 



The Loaches, Cobitidinae, which form a very natural sub-family, 

 are small fishes, few species growing to a foot in length, mostly 

 living in small streams and ponds. Many delight in the mud 

 at the bottom, in which they move like Eels. In some cases, the 

 branchial respiration appears to be insufficient, and the intestinal 

 tract acts as an accessory breathing organ. The air-bladder, 

 which is partially encased in a bony capsule, may be so reduced 

 as to lose its hydrostatic functions and becomes transformed into 

 a sensory organ, its outer exposed surface being connected with 

 the skin by a meatus between the bands of muscle, and convey- 

 ing the thermo- barometrical impressions to the auditory nerves ; 

 hence the name of " Wetterfisch," by which Loaches are known 

 in some parts of Germany. 



The Homalopterinae are more or less perfectly adapted to life 

 in rapid streams, the most remarkable in this respect being 



^ Watase, Journ. Coll. Sci. Japan, i. 1887, p. 247. 



