GUDGEON AND ROACH. 107 



plentiful. They are ground- feeders and are not very fastidious in 

 their diet. The Barbel is rarely eaten except by the poorest 

 people, its liability to convey tape-worms unless the flesh be very 

 thoroughly cooked rendering it undesirable for the table. The 

 roe, also, is sometimes poisonous. 



The Gudgeon. Gobio fluviatilis (332), is a small fish similar in Gudgeon. 

 general proportions to the Barbel, but having only two barbels 

 instead of four, and lacking the spine in front of the dorsal fin 

 which the Barbel possesses. The Gudgeons prefer clear running 

 water, although on the continent they are found in still lakes. 

 They are gregarious, moving about in large shoals ; they feed on 

 small animals, such as insect larvae, crustaceans and worms. In 

 England the Gudgeon grows to six inches. 



The species of Leuciscus, known in a general way as " White- Roach, 

 fish," are abundant in the temperate parts of Europe, Asia and C|iub, 

 North America. Of the European forms the commonest are the &c. 



Fig. 54. — Lower Pharyngeal Bones of the Chub, showing the teeth. 



Roach, Leuciscus rutilus, 341, spread all over Europe north of the 

 Alps ; the Chub, Leuciscus cephalus, 338, with a more southern 

 distribution, extending even into Asia Minor ; the Dace, Leuciscus 

 vulgaris, 343 ; the Ide or Nerfling, Leuciscus idus, in the northern 

 and central parts of Europe, but absent from Britain ; the Rudd 

 or Red-eye, Leuciscus erythrophthalmus, 335 ; and the Minnow, 

 Leuciscus phoxinus, 334. The scientific differences between the 

 above species are based on the position of the dorsal fin, the 

 number of scales in the lateral line, the arrangement of the pha- 

 ryngeal teeth (see fig. 54), and the numbers of fin-rays in the 

 several fins. 



The Roach grows to 2 or 2£ lbs. The Rudd is deeper in 



