SERTULAEID^. 



203 



the Greek word for sharp ; hut we think with Dr. Johnston, that it 



more probably is a 



mis-spelling of Thoe, 



one of the Nereids, 



nymphs of the sea. 



They are generally of 



a brown and yellow 



colour, branched, and 



from an inch and a 



half to six inches in 



height. 



Sertularia pu/mila. 

 — This is parasitic, 

 and spreads its brown- 

 coloured shoots over 

 various fuci and sea- 

 shells; but rarely at- 

 tains more than half 

 an inch in height. 

 Stewart says, this 

 species, and probably 

 many others, in some 

 particular states of the 

 atmosphere, emits a 

 phosphorescent light 

 in the dark. If a leaf 

 of the above fucus 

 (serratus), with the 

 Sertularia. upon it, re- 

 ceives a smart stroke 

 in the dark, the whole 

 . coralline is most beau- 

 tifully illuminated, ev- 

 ery denticle seeming 

 to be on fire. 



Sertularia Hiber- 

 nica is thus named 

 from being found near 

 Donaghadee; Tem- " 



nlptrm savs "The fig. 106; Haliotus, Pollicipes, Chiton MargincUus ; 



P •! ' . Eggs of Cuttle-fish, or Sea-grapes ; Armeria mariHma, 



branching, of this and other sea-side plante. 



