152 POPULAR HISTORY OF THE AQUARIUM. 



The Medusa first gives bii'tli to numbers of minute balls, 

 or eggs of jelly covered by a thin skin studded with vibra- 

 tile hairs. The action of the hairs enables this germ or 

 spherule to swim through the water. They are nearly oval 

 bodies but rather wider at one end than at the other, and 

 they are propelled with the larger end foremost. After 

 swimming about for some time, the larger end turns down- 

 wards towards the ground, and attaches itself to some sub- 

 marine object convenient for the purpose. Presently the 

 body lengthens, and at the same time becomes wider at 

 what was before the narrowest end, and then there is 

 formed in the centre of that end a mouth, at first a mere 

 opening of small dimensions, but soon enlarging- and be- 

 coming surrounded by four prominent lobes or lips. These, 

 increasing in length, are changed to long thin tentacula, or 

 feelers, between which new tentacula make their appear- 

 ance, till the whole thing assumes the appearance of a kind 

 of cup-flower with long petals, and is, in fact, a Hydra-like 

 polype, fixed on a stalk. This is the Medusa-hul, from 

 whose sides new buds of the same character and appearance 

 grow out, each one beginning like a small tubercle, stretch- 

 ing out till it reaches something to which it can attach its 

 apex, and then, detaching itself from the other bud, grows 



