THE SEA-WEEDS AT HOME AND ABROAD. 293 
in spite of the obstacles in correctly addressing them by 
their correct names, attract the attention of the most 
superficial. They are not difficult to find, and the same 
efforts to secure other and more specious kinds will insure 
many of these. 
The Melanosperms, black or fuscous seeded sea-weeds, 
less comely and attractive but by far more useful to savage 
and civilized man alike, remain for a cursory glance at least. 
Although our species are of only a respectable size when 
compared with foreign kinds, yet they assist so much in pro- 
ducing the effect we witness, wherever the ocean impinges 
on the land, we can illy spare them. Investing rock and 
wood structures alike, if built in places subject to the varia- 
tions of the tides, they bear exposure of a few hours to the 
dry atmosphere or seorching sunshine, and revive as the 
cooled waters return to cover them, forming safe retreats to 
fishes, mollusks and other marine creatures, and affording the 
most nutritious dressings by way of manure to the exhausted 
fields. The variety of forms which they present has caused 
them to be comprised in several families with subdivisions 
arranged in such a way that they can be more readily studied, 
and those will claim our notice. About our shores the most 
abundant sea-weed of this kind is the fucus, of which there 
are two or three species and several varieties; or according 
to Professor Harvey five species on the American and seven 
species on the European shores, and one allied to F. nodosus, 
found at the Cape of Good Hope. They are usually known 
as kelp weed, rock weed, etc. Their seeds are lodged in 
tubercles filled with mucus, and they are discharged through 
the small pores; the hollow vesicles by which they are 
buoyed up in the water are not the seed-vessels but air 
bladders. A section of one of these seed tubercles, under 
the microscope, affords an instructive and pleasing sight. The 
Halidrys siliquosa might be readily taken for a narrow 
fronded fucus, but the air vessels are singularly divided 
transversely by numerous diaphragms extremely thin and 
