SENSES AND NERVES I29 



came across during his rambles. Gosse therefore invented 

 an Enghsh name for each kind because until he popularized 

 them they had only scientific ones in Latin. He made the 

 names descriptive, some quite straightforward such as the 

 Rosy, Scarlet-fringed and Snake-locked anemones; but he 

 also produced a series of diminutives, and without a smile 

 dubbed these beautiful creatures the Warted Corklet, the 

 Eyelet, Opelet, Trumplet, Beadlet, the Glaucous Pimplet, 

 the Arrow Muzzlet, and others. 



If you come across a Dahlia Wartlet in a rock pool on 

 the beach at low tide expanded in all its glory, with brightly 

 coloured tentacles swollen and translucent from the pressure 

 of the fluid inside, and you prod it with the end of a stick, 

 it is almost instantly transformed. The tentacles fold in over 

 the disc and disappear inside as the stalk contracts, so that 

 the animal-flower of a moment ago becomes a rounded 

 conical lump of jelly with a puckered hole at the summit. 

 The stimulus received by the sensory cells on the surface 

 has been sent through the conducting paths of the nerve net- 

 work to all the muscle cells in the body which have responded 

 by contracting, and pulling the animal into a shape and size 

 least vulnerable to danger. But even the diffuse nerve net- 

 work of the Wartlet does not trigger a random or simul- 

 taneous contraction of all the muscular tissue ; the folding up 

 of the anemone is an orderly process — first the tentacles 

 contract and fold inwards, then they are drawn down with 

 the disc while the stalk contracts. Although it all happens 

 very quickly the movements are co-ordinated so that the 

 body does not, for example, shut the tentacles out by con- 

 tracting before they have folded inwards. 



Sea-anemones are sensitive to other stimuli besides the 

 simple one of touch. Like the Amoeba, they respond to 

 chemical stimuli, that is to substances dissolved in the water 

 and producing what we should call tastes or odours. They 

 also react to light ; Gosse tells us that "it is under the veil 

 of night that the anemones in general expand most readily 

 and fully. While the glare of day is upon them, they are 

 often chary of displaying their blossomed beauties ; but an 

 hour of darkness will often suffice to overcome the reluctance 

 of the coyest." They are, however, not equally sensitive to 



