102 ELEMENTARY ZOOLOGY 



substance scattered here and there on the sand. These 

 are the bodies or parts of bodies of jellyfishes which have 

 been cast up by the waves. Exposed to the sun and 

 wind the jelly-like mass soon dries or evaporates away to 

 a small shrivelled mass. The body-substance of a jelly- 

 fish contains a very large proportion of water; in fact 

 there is hardly more than I per cent of solid matter in it. 



The jellyfishes occur in great numbers 6n the surface of 

 the ocean and are familiar to sailors under the name of 

 "sea-bulbs." Some live in the deeper waters; a few 

 specimens have been dredged up from depths of a mile 

 below the surface. They range in size from " umbrellas " 

 or disks a few millimeters in diameter to disks of a 

 diameter of two meters (2\ yards). 'They are all car- 

 nivorous, preying on other small ocean animals which 

 they catch by means of their tentacles provided with 

 stinging-threads. The tentacles of some of the largest 

 jellyfishes "reach the astonishing length of 40 meters, or 

 about 130 feet." Many of the jellyfishes are beautifully 

 colored, although all are nearly transparent. Almost all 

 of them are phosphorescent, and when irritated some 

 emit a very strong light. 



The sea-anemones and corals (Actinozoa). Almost 

 everywhere along the seashore where there are rocks and 

 tide-pools a host of various kinds of sea-anemones can be 

 found. When the tide is out, exposing the dripping sea- 

 weed-covered rocks, and the little sand- or stone-floored 

 basins are left filled with clear sea-water, the brown and 

 green and purple "sea-flowers " may be found fixed to 

 the rocks by the base with the mouth-opening and circlet 

 of slowly-moving tentacles hungrily ready for food 

 (fig. 1 6). Touch the fringe of tentacles with your finger- 

 tip and feel how they cling to it and see how they close in 

 so as to carry what they feel into the mouth-opening. A 

 host of individuals there are, and scores of different kinds; 



