COURTSHIP AND NURSERY DUTIES. 113 



masses take the form of long tube or net-shaped 

 bands, which are deposited on, and adhere to, 

 water-plants at the bottom of the stream. It is 

 interesting to remark that, rope-like masses of this 

 kind are also laid by the common toad. The 

 eggs of the fishing-frog (Lophius piscatorius) are 

 similarly invested by a gelatinous outer coat, and 

 form a floating sheet of from 60 to 100 square 

 feet. Floating masses such as this are rare 

 amongst fishes. The eggs of the herring are 

 laid comparatively near land, and in masses. 

 They are viscid externally, and adhere to any 

 object with which they may come in contact on 

 the sea-bottom. 



In the plaice and cod-fish and the allied species, 

 the eggs are buoyant, and laid in enormous num- 

 bers at a variable distance from shore. They 

 float just below the surface, and drift accordingly 

 at the mercy of wind and tide. 



The size of the egg depends probably upon the 

 number; and the number varies probably as 

 the risks to which they are exposed. How 

 variable the number may be we may gather from 

 the fact that in the closely allied members of the 

 lamprey tribe, Myxine and Lamprey, the former 

 lays probably not more than 30, the latter about 

 30,000. The sturgeon lays about 7,000,000 ; the 

 herring about 25,000 ; lump-fish, 155,000; hali- 

 but (which lays a relatively large egg), 3,500,000; 

 cod-fish, 9,344,000; ling, 150,000,000. 



The number of the eggs deposited by each par- 

 ticular species of fish, it has just been remarked, 

 depends largely upon the risks from destruction 

 to which they are exposed. These risks are 

 H 



