3io 



LO WER FORMS OF MARINE LIFE 



the belief that they live upon large animals, but their food consists partly of small 

 organisms and partly of animal and vegetable matter. A common species of the 



European seas is the edible 

 urchin {Echinus esculen- 

 tus), which is about 6 inches 

 across, and has a scarlet or 

 brownish shell, and short 

 spines, which range in 

 colour from white to purple. 

 Its shape is almost circular, 

 but that of many other 

 species is oval. Another 

 noteworthy species is the 

 sea-porcupine (Echinothrix 

 calamaris), so called from 

 the alternately light and 

 dark rings on its longspines. 

 The vast majority of ccelenterates inhabit the sea, those restricted 

 to fresh water being very few. There are three classes in the sub- 

 kingdom, and an excellent example of the first is afforded by Syncoryne sarsi, which 

 in its free state is known as Sarsia tubulosa, one of the Hydromedusse. In shape 



SEA-POECUFINE. 



Ccelenterates. 





. 



SAILING JELLY-FISH. 



this resembles a club with from twelve to sixteen tentacles, and is about half an 

 inch high. It grows in colonies which fasten themselves to wood-work, seaweed, 

 and the like, in the North Sea and Baltic, at a depth of from 2 to 8 fathoms, and 

 the free form buds forth from the club-shaped body. This attains a breadth across 



