COHEGOXUS \VARTMANNI. 343 



entire at the margin, and overlapping nearly half their diameter. They are 

 smallest on the back, throat, and bases of the pectoral and caudal fins. The 

 spine-like scale over the base of the ventral is long, and ends in a membranous 

 point. The lateral mucus-canal runs in a nearly straight line above the middle 

 of the height of the side, and opens with simple pores. The suborbital branch 

 of the cephalic canal is strongly developed, and is sunk so deeply in the bone 

 that the suborbital ring appears to be double. 



The colour of the upper part of the head and back, as far down as the lateral 

 line, is blue and silvery. The sides of the head, and the abdomen are silvery. The 

 lateral line is spotted with black. All the fins are yellowish-white with broad 

 bluish-black edging, which is especially marked in the ventral and anal fins. 

 The iris is silvery. In Lake Constance the fish is sometimes dark in colour. 

 In young individuals the fins are colourless.. The common length of this fish 

 is from fifteen to eighteen inches, when it usually weighs from one and a half to 

 two pounds ; but the length varies from nine to twenty-eight inches, and it 

 passes under different names among fishermen, according to its size. It has 

 fifty-nine to sixty vertebrae. 



This species stocks certain lakes almost to the exclusion of other fishes, and 

 is particularly common in the Atter See, Gmiinden See, and Fuschler See, in 

 Austria, and is found in most of the large lakes in Austria, Bavaria, and 

 Switzerland, especially in Lake Constance. According to Blanchard and 

 Moreau, it is found in Lake Bourget, and other places in the east of France. 

 It usually lives at a considerable depth, and in cold weather descends deeper, 

 often going down to a hundred fathoms. 



Spawning-time is somewhat uncertain, taking place in spring, summer, and 

 autumn, according to different observers ; according to Von Siebold, in Novem- 

 ber and December ; February and March/ according to Heckel and Kner. Most 

 fishes then come into shallow water, but this species keeps at a depth of ten 

 fathoms. The spawning lasts for about fourteen days or three weeks, when the 

 fishes collect in immense numbers, and many are so pressed together that the 

 scales on their sides are rubbed off and float for some distance over the surface 

 of the water above the spawning ground. It does not spawn till ten to twelve 

 inches long. 



This species lives on worms, insect-larvae, the spawn of other fishes, and 

 many kinds of animal life, as well as vegetable substances. It does not eat 

 when spawning. It increases rapidly ; but is not tenacious of life, dying as 

 soon as taken out of the water. 



These fishes are greatly eaten by Trout. They are taken with large nets 

 sunk deep in the lakes at spawning-time, and their capture constitutes an 

 important local trade. They are eaten fresh on Lake Constance and other 



