
SEA-WEEDS. 227 
Coating the surface of the wet rocks, like a short pile 
of green velvet, grows the Calothrix scopulorum; tread 
warily upon it lest you catch an unpleasant fall from its 
sliminess ; it will reward you if looked at through the mi- 
eroscope. The surface of the rocks where it shows beneath 
the water is rich with crimson, owing to the Hildenbrandtia 
sanguinea, a species which I detected in company with a 
submarine lichen, a dark olive-green crustaceous species, 
the Verrucaria maura, the former being unknown to Pro- 
fessor Harvey as a North American plant when he published 
his Nereis Boreali-Americana, which describes our sea- 
weeds. In similar tide-pools I found, at Marblehead near 
the fort, the singular Peysonella orbicularis; and on smooth 
pebbles under the water, circular patches of a pale-pink 
crust, which are the Melobesia. These, cut with a sharp 
knife into very thin slices across the warts which rise from 
the surface of the patches, will show, when magnified, the 
seeds lodged in minute cavities and the cellular structure of 
the frond. Lining the sides of these basins are the pretty 
coral sea-weeds, which fade so soon after drying, once 
thought to be, and described by Lamaroux, as animals, but 
now known as lime-bearing sea-weeds ( Corallina officinalis) , 
the actual frond being covered with a calcareous crust, which 
the plant has extracted and secreted from the sea. Throw a 
tuft of it into some diluted muriatic acid, the plant within 
will be revealed ! The seed-vessels are elegantly formed, 
urn-shaped, but closed caskets, on the very tips of the 
branches : 
Here also grow the glossy green Cladomorpha, and the 
fistulous, swollen Enteromorpha, both of many kinds; and 
where the water is brackish, like the broad overflowed 
ditches on the salt-marsh in rear of the beach, may be 
Seen in vast floating masses, smooth and slimy, or bullate 
= bladdery, of a pale -yellow-green tint in the sun, and 
mte and like paper when lying dry and dead on the grass, 
the Conferva Jlavescens, which, taken up by the winds and 

