THE LOACH 213 



Bleak is one of the parents, but leave it in doubt 

 whether the Chub or the Dace is the other; the 

 Chub differs from the Dace in the larger mouth 

 and broader head, whilst the scales are somewhat 

 fewer and the free edges of the dorsal and anal 

 fins are convex instead of concave. All these 

 characters come out to a greater or less extent 

 in the hybrid fishes here described and establish 

 their Chub parentage pretty conclusively. The 

 mouth is a little larger than in either the Dace 

 or the Bleak, the length of the lower jaw measuring 

 more than one-third that of the head ; the inter- 

 orbital space is broader than in the Dace and much 

 broader than in the Bleak, its width being con- 

 tained two and three-fourth to two and four-fifth 

 times in the length of the head ; the scales in the 

 lateral line number forty-five to forty-eight, averag- 

 ing forty-six, whereas the average number in Dace 

 and Bleak is about fifty ; the free edges of the 

 dorsal and anal fins may be either very slightly 

 concave, straight, or a little convex. 



This hybrid sometimes attains a length of a foot, 

 a size which also points to the Chub rather than the 

 Dace as one of the parents ; the example figured 

 (PI. XXXI, Fig. 2) is nearly half that length'. 



THE LOACHES (Cobitidce) are closely related to 

 the Carp family, from which they differ in having 

 the reduced air-bladder partly or wholly enclosed 

 in a bony capsule, whilst the pharyngeal teeth, 

 arranged in a single series, are rather more numer- 

 ous than in the Cyprinoids, and the pad against 

 which they work in the latter group is absent. 

 Externally the Loaches may be recognized by 



