12:> THE FRESH-WATER FISHES OF EUROPE. 



than the first membranous ray; its hinder side is toothed, with the denticles 

 directed downward. The anal fin has a shorter base than the dorsal, is more 

 pointed, and varies in length, but does not reach back to the caudal. 



The caudal fin is deeply forked, and its lobes are usually equal. The 

 lateral line is approximately parallel to. the ventral outline ; its last three 

 scales are on the base of the caudal fin. 



The cephalic canals are well developed behind the eye, and at the forward 

 angle of the operculum the free edge of the pre-operculum is slightly 

 pitted. The largest scales lie behind the shoulder-girdle, the smallest on 

 the anterior part of the back. The free border of the scale is convex, 

 and marked with many fine radiating Hues. 



The colour varies with conditions of life. In the muddy waters of the 

 Tagus the fish is of a dirty yellowish-brown, while in the Guadiana, where the 

 water is clear and the bed rocky, the colour is blue-grey with a metallic 

 lustre, becoming silver-grey on the belly. The unpaired fins are usually 

 spotted black, and a black band margins the base of the opercular region. 



The species is not common in the Lisbon market, but is abundant at 

 Toledo, where the local name for it is Comba. It is regarded by the fishermen 

 of Mertola, on the Guadiana, as the male of Chondrostoma willkommii. 



Dr. Steindachner is of opinion that crosses occur between Barbns corniza 

 and Barbus bocagei; and since some fishes have the characters of Barbtis 

 comiza, with the jaws and mouths of Ckondrosloma pofylepis, he regards 

 such individuals as hybrids. But Dr. Giinther remarks that a similar com- 

 bination of characters distinguishes certain Cyprinoid genera of Western 

 Asia. 



Barbus bocagei (STEINDACHNER). 



The body of this species is much compressed and elongated. The pro- 

 portion of length of the head to the body is as one to four and five-sixths. The 

 height varies with age, the fish becoming more slender as it gets older. 

 The diameter of the eye is one-fifth to one-seventh of the length of the head, 

 and the eye is more than twice its own diameter from the extremity of the snout. 

 The gape of the mouth is small. The upper lip varies in thickness, and the 

 snout extends over it. The barbels of the upper jaw do not reach back 

 quite so far as the orbit of the eye. The barbels at the corners of the mouth 

 reach across the orbits. The profile of the head is slightly arched, and thence 

 extends in a convex curve to the dorsal fin, much as in Barbus vidyorix. 

 The least height of the tail is equal to about one-half of the greatest height 

 of ths body. 



The dorsal fin commences in front of the ventral, is in advance of the 



