GOBIO FLUVIATITJS. 



129 



its length. The horizontal mouth is covered by the fleshy lips, and does not 

 reach back so far as the nasal apertures, which are near the eyes. Fig. 58 

 shows the pharyngeal teeth. The short barbels are at the corners of the 

 mouth. The form of the head (Fig. 57) varies so much, especially in length, 

 that we might be inclined to suspect specific differences in diverse individuals 

 were it not for the insensible gradations by which the extreme forms are 

 connected. The frontal outline rises from the blunt nose to the hinder region 

 of the head in a regular arch, which becomes more flattened towards the dorsal 

 fin. The greatest depth of the body is two and a half or two and a third 

 times the depth at the tail. 



The dorsal fin is rather less than half-way down the body, and commences 

 a little in front of the ventral fin. It is higher than long. Its height is almost 



Fig. 56. GOBIO FLUVIATILIS (RONDELETIUS). 



equal to the depth of the body, but the last ray is only half as long as the 

 first branched ray. The anal fin is placed well behind the termination of the 

 dorsal. It is less developed than the dorsal, is similarly truncate behind, 

 and higher than long. The ventral fins nearly reach to the anal, and always 

 cover the vent. The pectoral fin, which 

 is as long as the dorsal is high, reaches 

 back as far as the beginning of the dorsal. 

 The caudal fin is evenly lobed and forked, 

 with its outer rays longer than those of 

 the dorsal. 



The back and sides are blackish-grey, 

 sometimes brown or even fawn colour, 

 spotted with dark green or black, especially 



along the lateral line and back. Sometimes there are about seven ocellate spots 

 in the lateral line, which have often a tendency to pass into a band. The 

 9 



Fig. 57. HEAD OF GOBIO FLUVIATILIS, 



SEEN FROM ABOVE. 



