212 



LEISURE-TIME STUDIES. 



turn depend for sustenance. Such a veritable animal tree,, 

 growing rooted and fixed to some object, increases by a 

 veritable process of "budding." As the animal buds die 

 and fall off, new buds are thrown out and developed to 

 supply the place of the lost members; the zoophyte, like 

 the tree, renewing its parts according to the strict law of 

 likeness, and each new member of the colony bearing as 

 close a likeness to the existing members as that borne by 



d 



FIG. 29. Zoophytes : b and d, showing the cells in which the animals live, are 

 magnified portions of a and c respectively. 



the one leaf -of a tree to its neighbouring leaves. But, as. 

 the tree sooner or later produces flowers which are destined 

 to furnish the seeds from which new trees may spring, so 

 the zoophyte in due time produces animal buds of a kind 

 differing widely from the ordinary units which enter into its 

 composition. These varying buds in very many cases appear 

 in the likeness of bell-shaped organisms, and when they 

 detach themselves from the zoophyte tree and swim freely 

 in the surrounding water, we recognise in each wandering 

 bud a strange likeness to the familiar medusae or jelly-fishes 

 which swarm in the summer seas around our coasts. Living 

 thus apart from the zoophyte-parent, these medusa buds may 

 pass weeks or months in an independent existence. Ulti- 



