Frogs and Toads 



From time to time he looks to see that all is well, but woe 

 betide any intruder who tries to enter his domain ; retri- 

 bution will be levied, and quickly. In due course the 

 yellow eggs turn brown, a sign that the young sticklebacks 

 will soon appear. When they do so, they, being like all 

 other children, are anxious to see the world, and then the 

 real cares of the father stickleback begin, for he is kept 

 very busily employed driving them back to the safety of 

 the nest till such time as they are able to fend for 

 themselves. 



The habits of the fifteen-spined stickleback are very 

 similar. His nest is built of seaweed, interwoven by 

 threads of a substance given off from his own body, and 

 suspended from a frond of a larger seaweed growing in 

 some sheltered pool. The eggs of this fish are as large 

 as those of the fresh-water stickleback were small ; in fact 

 few fishes lay larger eggs in comparison to their size. 



A very remarkable adaptation for securing the safety 

 of its eggs has been described in a small fresh-water fish 

 from New Guinea. The eggs are surrounded by coiled 

 filaments, closely wound, like the india-rubber thread in 

 the core of a modern golf-ball. When they are laid, the 

 filaments uncoil automatically, and the eggs are bound 

 together in a double bunch, like a double bunch of onions. 

 At the same time on the skull of the male fish there is a 

 small bony process, like a bent finger, growing forwards 

 and downwards. Just before the hook process becomes 

 an " eye," the double bunch of eggs is in some way or 

 other slipped in ; as the " eye " is completed it is fixed, 

 and the male goes about with the developing eggs on 

 the top of his head. This case is particularly interesting 

 because the two adaptations, which so perfectly fit, are, 

 as it were, very far apart the filaments round the eggs 

 and the bony process on the male's head ; of this the female 

 shows no trace. 



The sea-horse, that eccentric-looking, upright-swimming 

 little individual so common in the Mediterranean, is a 



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