116 SEX-LORE 



advanced type of brood-care known among the 

 fishes. The male begins his labours by building a 

 nest; this is made from leaves, twigs, bits of weed, 

 and straw. He works the material with his tail into 

 a loose circular structure, weighting it with sand and 

 gravel if the current of the strep m is too strong, and 

 binding it with mucus. When this work is com- 

 plete, he goes in search of a female and drives her 

 into the nest not unlike the early wife-marauders; 

 there she is kept until she has laid her eggs, which 

 he then fertilizes. Having deposited the eggs, the 

 female wriggles out again, and does not trouble about 

 them any more; but the male takes up sentry duty, 

 mounting guard against all comers at the entrance 

 of the nest. If other fish approach, he dashes at 

 them, and has been known to attack bigger fish than 

 himself, in some cases losing his life in the struggle a 

 beautiful example of parental sacrifice for the young, 

 and in this instance by the male and not the female. 

 When the eggs are hatched, he still keeps watch over the 

 young, of which there are about fifty. This continues 

 for six or seven days, but the young become too rest- 

 less in their search for food and finally wander away. 

 Rising a step higher in the scale of animals, we 

 come to the amphibians and reptiles. It has been 

 mentioned in a previous chapter that the female frog 

 deposits her eggs in ponds and ditches, taking no 

 more care of them. Now there are some exceptions 

 to this rule; for certain frogs are provided with special 

 sacs for carrying the eggs until they are hatched. 

 Here again it is often the male that sees to the safety 

 of the larvae. " Among the pouched frogs of America 

 the skin on the back of the female is very loose, so 



