102 GENERA AND SPECIES. 



The other Sticklebacks are little better than varieties of one 

 species, and can only be briefly dealt with as such. As far as the 

 fins go they can be tabulated : 



No. 91. Dorsal, 3 spines and u rays; anal, a spine and 8 or 9 rays; 

 caudal 12 rays ; pectorals 10 to 12 ; ventrals, a spine 

 and a ray. 



No. 92. Dorsal, 3 spines and n rays; anal, a spine and 8 fays; 

 caudal 12 rays; pectorals 10 ; ventrals, a spine and 

 a ray. 



No. 93. Dorsal, 3 spines and n rays; anal, a spine and 9 rays; 

 caudal 12 rays ; pectorals 10 ; ventrals, a spine and a 

 ray. 



No. 94. Dorsal, 3 spines and n rays; anal, a spine and 8 rays; 

 caudal 12 rays; pectorals 10; ventrals, a spine and a 

 ray. 



No. 95. Dorsal, 4 spines and 10 rays; anal, a spine and 8 rays; 

 caudal 12 rays; pectorals 10 rays; ventrals, a spine 

 and a ray. 



The body is short and compressed, and not over 3^ inches long ; 

 in colour it is grey with greenish or golden reflections, and spots arid 

 stripes. During the breeding season the underparts are red. As 

 a rule these are inland fishes, but they descend the rivers 

 in shoals to the sea, so that they are fresh-water, estuarine, and 

 marine. When in sea-water they are darker and bluer in colour 

 than when in fresh. In fresh- water the male builds his nest of straws, 

 and lines and laces it with confervas, in sea-water he uses algae, as 

 does his fifteen-spined relative. 



Gobio. Plate xxii. CYPRINIDJE. 



173. fluviatilis. GUDGEON. Two small barbules; abdomen nearly 

 straight ; bands of spots on dorsal and caudal. 



The Gudgeon has 9 or 10 rays in its dorsal fin, 8 in its anal, 19 in 

 its caudal, 15 or 16 in its pectorals, and 8 or 9 in its ventrals. The 

 dorsal rises in the middle of the back, over the tip of the pectorals 

 and in front of the ventrals, the ventral being half way between the 

 pectorals and the anal. In the lateral line, which is straight, there 

 are from 36 to 44 scales ; the scales are large and angular. The 

 back is rather sharply curved, and is highest slightly in front of the 

 dorsal ; the abdomen is nearly straight from the jaw to the anal fin, 

 along the base of which it curves upwards, and continues almost 

 straight again to the caudal. The mouth is small, and the upper 

 jaw the longer, with a barbule at each corner like the end of a 

 moustache. In colour the Gudgeon is olive above and silvery below, 

 with lines of spots on the vertical fins. In length it reaches 8 inches 

 or more. In habits it is gregarious, and prefers running water with 

 a sandy or gravelly bed whereon it can feed on the molluscs, and 

 worms, and plants, but it is not particular as to the purity of 

 the water. 



