300 THE FRESH-WATER FISHES OF EUROPE. 



anterior eyelid is broad and large. The maxillary bone has an inclined direction, 

 and extends only slightly behind the eye. The jaws have rather slender short 

 teeth. On the vomer there are three transverse teeth in front, with a simple 

 longitudinal row of four on the body of the bone, and a zigzag row or double 

 row of eight or nine behind these (Fig. 159). 



The margin of the pre-operculum expands in the middle of the hinder 

 border. The number of branchiostegal rays of the right side is ten, and on the 

 left side eleven. The rake-teeth are thin, but long and pointed, and the last 

 arch carries nine or ten teeth. The dorsal and ventral profiles are similar. 



The dorsal fin begins in front of the middle of the length ; it is trun- 

 cate behind, nearly as high as long ; but its height is less than the depth of 

 the body. The anal fin is as high as the dorsal. The adipose fin is opposite the 

 end of the anal. The longest rays of the ventral are equal to those of the dorsal- 

 The scales are small ; smallest in the fore-part of the body and belly, and 

 easily fall off. The stomach is smaller than in the typical forms of Salmo 

 lacustris, but the pyloric appendages vary from sixty to seventy-four. 



The colour of the upper part of the head and back is black, with steel-blue 

 lustrous scales, the blue becoming paler towards the lateral line, and giving 

 place to silvery-white on the under side of the body. The operculum is also 

 silvery. The sides of the body are marked with irregular deep-black spots, 

 which are generally angular or cross-shaped, and of considerable size. They 

 are rarely round. Red spots are scattered between them; there are similar 

 spots on the operculum, but generally larger and rounder. Below the lateral 

 line the number of spots diminishes, and the belly may have a slight tinge of 

 red. The skin of the dorsal fin is dotted with black, and margined with a 

 broad, dark border. The pectoral fin is yellowish-white at the base, and 

 greyish at the upper side. The anal and ventral fins are whitish. 



The usual weight of the fish is from ten to fifteen pounds, though much 

 smaller specimens are commonly caught ; and occasionally individuals are 

 captured which weigh from thirty to forty pounds. 



During the greater part of the year the May Trout frequents the deep re- 

 cesses of mountain lakes, only leaving them in May. It then comes to the 

 surface, and pursues small fishes, on which it feeds in the morning and evening. 

 The Trout swim in large circles, and drive their prey into the centre, and then 

 rush at them. When thus engaged they are commonly caught with the net, 

 which is also drawn in a circle. They furnish good sport with the rod, and 

 may be taken in this way during a large part of the year. They die at once 

 when out of water, and live but a short time in ponds, even with a good supply 

 of food. They rarely go out of the lakes into the streams which flow into or 

 drain them. 



