SECT. in. DEVELOPMENT OF MEDUSA-BUDS. 



95 



ing their prey with their tentacles and digesting it in 

 their stomachs. The limits to this budding-system 

 seems to be indefinite : years may pass in this stage, but 

 at length it ceases, and either the original hydra, or one 

 of its descendants, undergoes a series of remarkable 

 changes. The body of the hydra lengthens into a 

 cylinder ; it is then marked transversely by a number of 

 constrictions beginning at the free end ; these become 

 deeper and deeper, till at length they break up the body 

 into a pile of shallow 

 cups, each lying in the 

 hollow of the other, and 

 leaving a kind of fleshy 

 wall at the point of sus- 

 pension or fixture. The 

 edges of the cups are 

 divided into lobes with 

 a slit in each, in which 

 the coloured rudiment 

 of the eye is sunk. The 

 cups are permanent, 

 and characteristic of 

 the group of naked- 

 eyed medusae. After a 

 time, the cups begin to 

 show contractile mo- 



tions, which increase 

 till the fibre of their 

 attachment is broken, 

 and then the superim- 

 posed cups are detached 



from flip rnlp rmp pffpr 



another, and swim freely 



away by the contrac- 



tions of their lobes as young medusae, leaving what 



remains of the parent hydra to repair its loss and 



Fig. 114. A,B, C,D, development of Medusa-buds; 

 o, polype-body; b, tentacles; c, a secondary 



le of tentacle s <*, proboscis; e, 



