Social Life in the Salt-JVatcr ITorld 23 



As the tide turns from high to low it leaves one un- 

 mistakable mark to indicate its highest level. This is 

 in the form of a long line of wilting seaweed and or- 

 ganic debris. Of this low-lying heap, by far the greater 

 portion consists of the common green seaweed, Ulva, 

 or sea lettuce, as it is popularly called. The sea lettuce, 

 having become detached from its anchorage on the 

 bottom, is carried ashore by wave action. Clumps ot 

 olivegreen and brown seaweeds sometimes are in the 

 mass, and often one will find those rarer and more 



orchestia; the sand flea. 



delicate forms, the brilliant red plants of the deeper 

 waters. Particularly are the latter in evidence after 

 a period of stormy weather. Often, too, a sponge is 

 torn from the outlying bottom and drifts about, finding 

 its way at last to the tangled tide mark on the shore. 

 As far as one can see, this telltale line extends itself 

 along the beach. At first sight it would appear that the 

 moist mass is destined shortly to become a heap of 

 rotting refuse. It is not, however, so destined. Barely 

 does it become stranded by the tide when it is beset by 

 a swarming population. Flies, beetles, and other in- 

 sects are engaged in its reduction. But the most active 



