ASPIUS RAPAX. 



231 



Those on the back aud abdomen show numerous regular diverging rays, but 

 the scales on the sides have only two to four rays. The largest scales are 

 found over the lateral line, but they do not attain the diameter of the eye. 

 Between the anal and ventral fins the abdomen forms a blunt keel, which 

 is not covered with overlapping scales, as in Alburnus, but the scales meet 

 each other irregularly in the median line. 



The mucus-canal of the head is well marked, especially in the frontal 

 region, along the pre-operculum and the lower jaw. The sub-orbital branch 

 extends in front of the nares. The accessory gills are large and fringe-like. 



The rake teeth of the gill-arch are rather short and far apart. Fig. 129 

 shows the pharyngeal teeth. 



The back of the fish is of a blue-black colour, the sides are bluish-white, 

 and the abdomen quite white. The dorsal and anal fins are blue; the 

 other fins have a reddish tinge. The iris is yellow, with some green stripes. 

 The fish does not exceed a length of two to three feet, or weigh more than 

 twelve pounds. 



It is commonly found in lakes and rivers flowing through level country, 

 for although it requires pure water, it objects to water flowing rapidly. It 

 lives upon vegetable matter, worms, and 

 small fishes, especially of the genus 

 Alburnus. It spawns in April and 

 May, when it enters shallow streams. 

 From eighty to one hundred thousand 

 eggs are deposited on stones. 



It is easily taken in the autumn 

 and at spawning-time, either with the 

 net, or rod and line, baited with a small 

 fish. The males at spawning-time have 



the scales largely covered with white conical spots, which, as in other species, 

 characterise the hinder border of the scale. 



The fish grows quickly, and lives for seven or eight years. 



It is common in Norway and in all streams flowing into the North or 

 Baltic Sea, extends through Russia, and is found in Pomerania, and the Haffs, 

 Central Europe, and Austria. A nearly allied species is found in the Tigris. 



Fig. 129. PHARYVGEAL TEETH OF ASl'ITJS 

 RAPAX. 



