OYSTERS 139 



intelligence of the male would expect) put into practice 

 by the male parent. Thus, there is a large fish in 

 tropical rivers which takes the eggs laid by the female 

 into his capacious mouth, and swims about with them 

 for three or four weeks, giving them the advantage of 

 a current of water which runs through his mouth to his 

 gills. When the young hatch they swim out of their 

 fond father's mouth. The male of pipe-fishes and of the 

 little " sea-horse " receives the eggs laid by the female 

 into a pouch excavated along his ventral surface. There 

 the young hatch, and are guarded by the nursing father. 

 On the other hand, some fathers impartially eat their 

 own young, as well as those of other parents, and the 

 mother has a hard job to protect her offspring. A female 

 octopus (the poulp or eight-armed cuttle-fish) sits over 

 her eggs in a nest built of pebbles at the bottom of the 

 sea (or of an aquarium tank in the instance studied by 

 me many years ago at Naples), and squirts a stream of 

 pure sea-water over them. She resents the approach of a 

 fish or a crab or a landing-net with splendid fury and 

 recklessness of attack. Often the males of fishes, frogs, 

 and birds guard the eggs, or guard the nest where the 

 female is occupied in caring for the eggs or the young. 



There are various species of oysters common in 

 all parts of the world which are eaten as delicacies. 

 Primeval (Neolithic) man ate oysters (the common sort) 

 in Denmark in enormous quantity great heaps of the 

 discarded oyster-shells are found, buried among which 

 are discovered stone axe-heads and bits of rude pottery. 

 In the West Indies travellers relate that the oysters 

 "climb" the trees which overhang the water of quiet 

 creeks and inlets of the sea. The fact is that the 

 branches of the mangrove trees dip into the water, and 

 the young oyster " spat " attaches itself to the immersed 

 twigs. After a year or two, the tree grows vigorously, 



