254 THE FRESII-AVATEK FISHES OF EUROPE. 



flecks in the median line of the back. The caudal fin is vertically striped; the 

 pectoral, ventral, and anal fins are uniformly pale. The iris is pale yellow. 

 This is the smallest species of the ""enus, reaching' a length of two inches 

 and a half in Austria, four inches in Germany and France, and three inches in 

 Great Britain. 



Like its allies it is very prolific. It spawns in March and April in France, 

 and in April or May in Germany and Austria, though Marsigli mentions 

 June, Its growth is slow. It is not sought after for food, on account of the 

 toughness of the flesh and the number of bones in it. When captured it 

 emits a peculiar sound. 



As in the preceding allied forms, the intestine has a respiratory function. 

 Coming to the surface the fish swallows atmospheric air, which is passed 



Ficf. 143.— roBiTis t.^-^nia, vak. elongata (heckei. and knek). 



through the intestine with some noise. Siebold suggests that this remark- 

 able habit has resulted from the way iu which the fish stirs up the mud, and 

 frequents places in which the supply of oxygen is small. It burrows like a 

 rabbit. The bony capsule for the air-bladder extends along two vertebrae 

 next the head. 



There is an elongated variety found in Croatia, which Heckei and Kner 

 describe as Cohilis elongata (Fig. 143). The height of the body may be only 

 one-tenth of the entire length. The double sub-orbital spine is small, and lies 

 under the skin. 



It further differs from C. tcenia in attaining a lai'ger size, being never 

 smaller than five inches, and usually six; yet in all general characteristics and 

 colour it agrees with the species under which we grou]) it. The body is five 

 and a half to six times as long as the head. The snout is more pointed than 

 in C. tcenia, so that the eye is farther from it than from the angle of the oper- 

 culum, while the distance between the eyes is scarcely half the orbital diameter. 

 Hence the forehead is smaller, and the head more compressed. The eye 

 is similarly covered with smooth skin. The barbels are longer, and those at 

 the angle of the mouth reach back to the front of the orbit, and are nearly 



