588 DESMIDS AND DIATOMS. 
multiplication, other than the development from eggs. It 
is true that the numbers of possible young contained in the 
roe of certain fishes far exceeds anything to be found in the 
case of either of the classes just alluded to, but of these 
comparatively few reach maturity ; while, slightly among 
the worms, still more among the flower-like mollusca, and 
in a most remarkable degree among the coral-polyps, a 
new mode of reproduction is introduced, by which not 
mere immature undeveloped individuals only are brought 
forth, but individuals fully formed, perfect in all their 
organs, ready to assist at once in the labors of the com- 
munity of which they form a part. 
Hence it is, perhaps, that the lower forms of life have 
been and are of incomparably more importance than the 
higher, in modifying the earth’s physical features, and in 
contributing material for its growth. The coral-polyp isa 
pigmy indeed beside the Mastodon, but while a fragmen- 
tary skeleton of the latter is here and there unearthed, the 
solid framework of the latter has, to a considerable extent, 
become also the framework of the globe, a portion of the 
masonry by which, tier upon tier, our continent has risen 
through successive ages. 
In passing from the Animal to the Vegetable Kingdom, 
the fact to which we have made allusion is equally appa- 
rent. Reproduction by seed, though the normal, is by no 
means the only nor indeed the usual method of propa- 
gation. Were this the case, and were every form of veg- 
tation but a single individual, how infinitely reduced 
ae be that individual’s chances of successfully resisting 
the thousand accidents to which it is subjected, how 
“infinitely less varied and less beautiful would be the de- 
S — of vegetable life. But every botanist knows, — 
- ' gardener practically proves, that a shrub or tree 
