a 
234 SEA-WEEDS. 















midrib running through the middle of each. They growin 
deep water, and several species are found in Massachus 
lately dedicated to Henry Grinnell, Esq., conspicuous in 
efforts to find Sir John Franklin; and its generic name, 
rived from his own, was given by Professor Harvey in 
Nereis Boreali Americana, some distinctive structure in th 
seed-vessel being detected by that botanist. The Grin 
being so abundant in New York harbor, may be s 
among our Delesserias. po 
The GELIDIACE®, like the last order, is also tropical 
mostly foreign. One or two species occur with us, such 
Gelidium corneum, a most variable plant, with a fork 
branched and pinnately divided frond, of a purplish-red, 
changing color, especially if immersed in fresh water 
finally parting with it altogether, but retaining 4 gl 
waxy lustre when completely bleached. t 
A rather singular Alga, found in our waters for the f 
time perhaps, by George B. Emerson, Esq., is the 4 
rotundus, a single genus of a single species, and consi™® 
the order Sponerocarre®, the seeds of which are fi 
irregularly shaped warts extending along the branchi 
pale flesh-color, wholly composed of slender, branched 
ments, like those of the bark, or cortex, of the frond 
tetraspores are formed in the upper branches deeply 
mersed. ; ha 
Passing over several other Algæ too rare on 0UFS” 
notice, or else already adverted to, we come to e 
RHODYMENIACE®, purplish or blood-red sea-We™ 
inarticulate, flat, compressed, or filiform membr 
fronds, the seeds lodged in external conceptacles. 
these to be sought is Rhodymenia palmata, with a e 
to eight inches long, and four to six inches broad, 
shaped at base, cut downwards into several slender j 
but sometimes quite simple; the Huthora cristata, 
