THE FIKST-TIDE POOL 35 



is usually at the tips of the branches, swollen termi- 

 nations yellow and slimy, full of dots or pores by 

 which the seeds are expelled. The manner of fructi- 

 fication is so interesting, and raises this seaweed so 

 high in the ranks of vegetable life, that a longer de- 

 scription will be useful to those who possess a good 

 microscope, and will be given presently 



Take these three abundant weeds as an easy lesson 

 in the observation necessary to the determining what 

 seaweed you have in hand 



Has the brown seaweed a mid-rib ? then it must be 

 either Fucus Serratus or Fucus Vesiculosus. But the 

 Bladder Wrach has long fronds from two to three feet 

 long, the air vessels as large as nuts, in pairs, the 

 fruit pods or receptacles also in pairs, and often forked 

 or heart-shaped. 



The Fucus Serratus is toothed or scolloped at the 

 edge, and both sides are dotted with pencil-like clusters 

 of fine white hairs ; besides which, the frond is often 

 covered or spotted with the most delicate lace-work, 

 which is the work of a tiny zoophyte with a very long 

 name — JHenibranipora : each mesh of that fairy-like 

 work was the dwelling of a perfect zoophyte; and 

 this patch of silvery lace is a city of the dead — the 

 habitations empty ; and when the bright waves close 

 over them, they become crystal caves, where minute 

 Crustaceans play or Infusoria hide. "We cannot easily 

 mistake between these two. 



If the Fucus has no mid-rib, it must be either the 

 Knobbed or the Channelled Wrack. 



Frcrs Ca^alictjlattjs, or Channelled, is found at 



c 2 



