102 SOME WONDERS OF THE SEA. 



the edge of the bell. In this form it is a Hydra, like 

 that of our fresh waters. Sometimes a slice splits off, as 

 if cut with a knife, very much as do the offsets of a tulip 

 bulb, and each slice becomes a separate Hydra capable of 

 undergoing its own development, and thus escaping the 

 two stages of egg and embryo. 



The polyp continues to grow, and then certain little 

 projections are seen upon various parts of the surface, 

 just like the buds of plants. The buds increase rapidly, 

 and become new polyps, throwing off secondary buds on 

 their own account. The bud is technically termed a 

 " gemma," to distinguish it from the offset, or " stolon." 



When these gemmas have attained their full growth, 

 a number of successive wrinkles surround the bell, and 

 divide it into deep rings. In this stage it bears a curious 

 resemblance to the grocer's salad-dressing bottles, where 

 the quantity of glass is supposed to compensate for the 

 paucity of its contents. 



The next stage is that each ring becomes notched 

 round the edge, so as to leave a number of projections. 

 These projections increase in length until they become 

 mere threads, while the divisions between the rings 

 becomes deeper and deeper, so that each ring, or disk, 

 as it has now become, is but slightly attached to its 

 neighbours by the centre. Lastly, the central attach- 

 ment gives way, the disks are set free, and each disk is 

 then seen to be a small but perfect Medusa. 



Such is a rapid and necessarily imperfect sketch of the 

 varied processes through which a Medusa has to pass 



