CGELENTERATES, SPONGES, AND PROTOZOA 157 



home". Then follows the sequel. "When put into the fresh 

 water the diseased -looking potato had fallen to the bottom 

 of the bottle, and lay there apparently dead as any potato 

 ever was. And now can words describe it? it was three 

 times its former girth, and rose up like some green-and-red- 

 striped cactus plant, two-thirds the height of the bottle, where 

 it burst into a myriad delicate grey-green petals, which merged 

 at their base into as delicate a pink, and they radiated at the 

 top exactly like the florets of a chrysanthemum, and in such 

 luxuriance that the bottle was not nearly wide enough for 

 their free expansion." Two brothers of unscientific tendencies 

 are then introduced to the marvel, " when someone, out of 

 the purest mischief, dropped one of my live shrimps right on to 

 the top of it, and then a curious thing happened. Instead 

 of the anemone closing up, it seemed to expand itself more 

 fully; the shrimp, after only one or two attempts to dart about, 

 was distinctly taken hold of, so to speak, by the petals or ten- 

 tacles of the anemone, and then it gave up in the most unexpected 

 manner all attempts even to struggle. When I say the ' petals ' 

 held the shrimp, they only seemed to touch it, and yet to securely 

 hold it. In fact the shrimp seemed to become paralysed and 

 utterly helpless, and then it was in a mysterious manner handed 

 along over the top of the tentacles, they all bending slightly in 

 sympathy towards the poor shrimp; and in, say, half a minute, 

 it disappeared, without a struggle, into the mouth in the very 

 centre of the creature, which, now that it behaved like an 

 animal, looked like nothing else than an elaborately-decorated 

 stomach." The present writer remembers on one occasion put- 

 ting some healthy whiting into a small aquarium containing 

 some expanded anemones. The fish came into contact with 

 the tentacles of these, and with startling result, for next moment 

 they were floating in a moribund condition, back downwards 

 at the surface of the water. It may be worth while to ex- 

 amine rather more closely the nature and action of the " net- 

 tling organs ", of which the action has just been described, and 

 which are potent enough in many cases to pierce the human 

 skin with painful results. Varying largely in the details of 

 their structure, these organs are present in most of the animals 

 included in the Anthozoa and Hydrozoa. The "nettling organs", 

 "stinging-cells", or "thread-cells", as they are variously called, 



