I.! i.'. I, /,',.', 



Fig. 14. More small jellyfish. 

 I, Laodicea undulata; 2, Obelia (see also Plate XII); 3, Rhopaloneiiia vclatuin; 4, Solinaris corona. 



with the stinging cells to capture unerringly a passing small fish or crustacean. 

 They are sensitive to light and the shallow water species will sink deeper into 

 the water in bright sunshine, returning towards the surface when a cloud 

 covers the sun, or as evening approaches. They swim by a gentle pulsation 

 of the bell and control their direction by inclining the bell in the direction 

 they want to go; they sink by just ceasing to pulsate. The larger jellyfish 

 (Fig. 16) have a special interest because their size makes them so familiar. 

 There are large numbers of tropical species but not so many in temperate 

 waters. The oceanic species may be carried into the shallower seas by ocean 

 currents but do not usually survive long and rarely, if ever, breed far out of 

 their normal habitat. The largest and best known are local species which live 

 and breed in shallow water. Of these the commonest is the moon jelly, 



50 



