50 COMMON SEAWEEDS. 



Mesogloia Vermicularis — is not so good a 

 species for the collector as for the microscopist : the 

 fronds are coarser, the colour a muddy olive or yellow, 

 the substance flaccid, and the form clumsy ; but the 

 fruit is most curious. At the tips of the branches a 

 spore is seated, dark olive green in a pellucid cell, 

 surrounded by filaments of gradually increasing round 

 cells, ending in a knob, and giving a singular appear- 

 ance to the tuft. 



These are both common in all tide-pools, from high 

 to low water mark. 



DUMONTIA. 



(Name in honour of Mons. Dtjmo^t, a French naturalist.) 



Generic character. — Frond from one to twenty 

 inches in length, a hollow tube filled with watery 

 gelatine, simple, rarely branched, of a red or purplish- 

 red colour. 



Fructification. — Groups of spores attached to the 

 inside of the membrane of the frond. 



GELIDIUM. 



(Name from gelu, frost, whence also gelatine ; and yet, says Haevet, 

 not one of the species is gelatinous !) 



A most difficult plant is this to describe with any 

 accuracy. It abounds in all our pools from high- water 

 mark to extreme low tide, and yet is so unlike itself 



