156 THE SEA-SIDE AND AQUARIUM. 



ren are so fond of treading upon, and cracking under 

 their feet. The noise they make is occasioned by 

 the explosion of the oval bladders that swell at inter- 

 vals upon each frond. 



Another plant, Fucus nodosus, is sometimes mis- 

 taken for the above, it also having oval bladders, 

 which serve to buoy up the plant amidst the waves. 

 But the distinction between the two is easily made, 

 by remembering that those of the latter are longer 

 and tougher, and will not break easily; although, 

 when thrown into the fire, they produce a loud re- 

 port. These bladders are sometimes made into 

 whistles by the juveniles, who, in consequence, have 

 a great penchant for the knobbed or knotted wrack, 

 as it is commonly called. 



This Fucus may be easily distinguished from the 

 common Bladder-wrack by the absence of a mid-rib. 

 I have a specimen before me that has a- beautiful 

 appearance imparted to it by the thick bushy tufts 

 of Polysiphonia fastigiata, that grows parasitically 

 upon it. This little plant has a pleasing effect, when 

 its hair-like filaments of deep purple colour are 

 spread upon white paper or card-board. 



Confined by the same string that binds the Nodo- 

 suSj and many other weeds that lie on my table, I 

 may mention the Fucus sermtus, another of the 

 Melanosperms. It has no vesicles upon its surface, 

 but it has something which is far more wonderful 

 and pretty. 



Its fronds are shaggy with the Sertularia pumila, 



