214 BRITISH FRESHWATER FISHES 



the elongate body, with the scales very small or 

 absent, and by the presence of at least six barbels. 



The fishes of this family are small, and numerous 

 species occur in the mountain streams of Central 

 and Southern Asia ; one species is known from 

 Abyssinia and three inhabit Europe, two of which 

 are found in our islands. 



It is well known that Loaches use their intestine 

 as an accessary organ of respiration ; when the 

 water is low or stagnant they come to the surface 

 and swallow air, which they afterwards expel through 

 the vent. 



Loaches are very sensitive to changes of atmo- 

 spheric pressure, so much so that in Germany one 

 species (Misg-urnus fossilis] is called ' Wetterfisch,' 

 foretelling stormy weather by becoming restless 

 and frequently rising to the surface of the water. 

 This peculiar sensitiveness is doubtless due to the 

 structure of the air-bladder, enclosed in a bony 

 capsule with an orifice on each side, from which 

 a duct, filled with a gelatinous substance, passes 

 between the main masses of the trunk muscles and 

 ends immediately beneath the skin just above the 

 base of the pectoral fin. Thus the internal ear is 

 brought into communication with the exterior via 

 the Weberian ossicles and the air-bladder. 



In the three European species of Loach, and 

 probably in many others, the air-bladder has no 

 open duct, and like many Cat-fishes with a reduced 

 and encapsuled air-bladder, they form an exception 

 to the statement that the fishes of the order Ostario- 

 physi are phyostomous. 



THE LOACH or STONE LOACH (Nemachilus barba- 



