BREEDING 293 



completed, may be used in the battles between rival males, in 

 nest building, or for a variety of purposes, including that of 

 assisting to hold the female and to facilitate the extrusion of the 

 ova by pressure on her body. All the Carps and their allies 

 breed in spring or early summer, and even the most sluggish 

 become intensely active under the stress of sexual excitement, 

 sporting at the surface and sometimes leaping clean out of the 

 water in their exuberance. As the time for spawning approaches 

 they congregate into shoals, and usually move into quiet, weedy 

 shallows near the banks of the rivers or in tributary streams. 

 Roach {Rutilus) are said to mass so closely together that by 

 their movements against one another they produce a kind of 

 gentle, hissing noise. In Norfolk they have been described as 

 crowding together among the rushes that fringe the banks in 

 such dense multitudes "that every instant one may see small 

 ones raised half out of the water by the passage of larger fish." 

 Whilst engaged in spawning most Cyprinid fishes seem to be 

 so intent on the business in hand that they are oblivious to all 

 danger, falling an easy prey to foes of all kinds. The attendant 

 males swim above or round the female, betraying great excite- 

 ment, and even pushing her abdomen with their snouts in 

 order to facilitate the extrusion of the ova, which are produced 

 at the rate of four or five hundred at a time, each batch being 

 promptly fertilised by the males. 



