DANGERS OP ROOKS. 



45 



and the mid-rib running up the centre of each 

 frond^ point it out at once. This plant, together 

 with one or two others of the sanae genus, is still 

 used in the manufacture of kelp, but not to 

 such an extent as was formerly the case. There 

 is a variety of this plant found in salt marshes, 

 where it congregates in dense masses : this variety 

 is very small, being only an inch or two in height, 

 and the eighth of an inch, or even less, in width. 

 The plant is at all times very variable, according 

 to its locality, both in colour and form. 



When trodden on, or otherwise suddenly comr 

 pressed, the air-vessels explode with a slight 

 report, and seem to afford much gratification to 

 juveniles. This and other fuci grow in the 

 greatest abundance on rocks that are covered by 

 the waves at high water, and left bare when the 

 tide retires. Now on, under, and among these 

 rocks, the great zoological or botanical harvest 

 is to be collected, and therefore among these 

 rocks the collector must walk. 



I make mention of this circumstance, because 

 it is necessary to warn the enthusiastic but 

 inexperienced naturalist, that the slimy and 

 slippery fuci make the rock-walking exceedingly 

 dangerous ; for the masses of fuci are so heavy 

 and thick, that they veil many a deep hollow. 



