illumines the little crystal globe, and marks out its course through 

 the water. Though individually minute, their numbers are so 

 numerous that they play an important part in the production of the 

 luminosity of the ocean. They project themselves by vigorous jerks, 

 contracting the tentacles at the same time ; in all cases their locomo- 

 tion is produced by alternate contraction and expansion of the bell." 



The tentacles are used for many purposes, viz. capture of prey, as 

 organs of attachment, and occasionally as legs. They are well armed 

 with stinging organs, similar to those possessed by the fresh-water 

 Hydra. 



When searching for food the Zooid will probably attach itself by 

 one or more of its tentacles to some object, and with the others, 

 which it has the power of elongating, it will search the surrounding 

 water, and woe betide any unfortunate creature that comes into 

 contact with them, for they proceed to draw it towards the mouth, 

 situated in the middle of the ring of tentacles, probably at the same 

 time paralysing it to prevent its struggles. 



In a large proportion of species the reproductive element is much 

 less conspicuous. The Gonozooid does not leave the parent colony, 

 but develops its offspring in situ. 



In the study of the embryology of these interesting little creatures 

 a gradual evolution is observed, from the simplest form to the most 

 complex medusa structure. 



In a species called Gonothyrea the young develops into a very 

 near approach to the medusa form, but does not leave the calycle. 

 When the ova are ripe they are scattered into the surrounding water, 

 and the Gonozooid withers away. 



There are other forms in which the young are cast forth, looking 

 very much like planaria, and are covered with cilia, enabling them 

 to swim freely. 



The embryo after a time enlarges at one extremity, and assumes 

 something of the appearance of a tadpole. This enlarged end, after 

 being attached to some piece of rock or seaweed, then expands into 

 a circular disc, the other part of the body standing at a right angle 

 to it. The embryo is now covered by a thin, chitinous envelope. 

 As development proceeds the free end is moulded into a beautiful 

 glassy, transparent, cup-shaped body, in which are formed the 

 tentacles, capable of extension and retraction ; the base becomes 

 modified into thre*td-like structures, enabling the organism to over- 

 come the action of the waves, which would tend to detach it from 

 its anchorage. As these little organisms swarm in sea-water, it is 

 easy to understand why such large colonies are formed. 



There are other modifications of development producing more 

 complex forms, which would take too long to describe this evening, 

 suffice it to say, that some are developed inside the gonotheca or 

 capsule, w r hilst others are ejected from the parent to go through 

 their changes as free swimming animals, each eventually settling 

 down and developing into a lovely plant-like animal. 



