GASTEROPODES. 327 
There is one singular fact connected with the history of the Doris 
and some more of the lower animals, wherein there is great distinction 
shewn between them and the higher orders. 
In the whole animated creation the unimpregnated ovum may sub- 
sist a long time without any important change, and in the course of its 
existence, it seems to resemble a portion of brute matter, yet endowed 
with such a living principle as preserves it from decay. 
In all the larger animals it seems that impregnation of the ovum is 
productive of the evolution of an embryo ; that the embryo requires a 
considerable time for attainmg maturity, in order that it may be sepa- 
rated with safety from the parent, and enjoy an independent existence 
as a perfect animal. 
But it is inanimate and motionless in the beginning, feeble and in- 
active in its progress, and at the moment of gaining maturity, still inca- 
pable, without some fostering aid, to provide for its own necessities. 
So there are many beings, and among them man, then ready to 
perish. 
The life, the growth, the changes undergone by the originating of 
the higher animals, are all carefully veiled from the inquisitive eye of 
mankind. If betrayed to view, it is generally by some fatal accident, 
precluding farther observation. 
It is absolutely the reverse with some of the lower animals. We 
nourish the Doris, it unloads its vast ovarium before us. Here we see 
innumerable ova, and in a brief interval as many embryos appear from 
them animated. But if those objects which we call embryos be truly 
the offspring of the Doris, they are void of all resemblance to the parent. 
Unlike the embryo of the larger animals, its activity is great from 
the ‘beginning, and it gradually augments, insomuch that when dis- 
charged as a mere speck from the spawn, wherein all are lodged, it has 
already attained in the earliest infancy infinitely greater powers than be- 
long to the oldest and most vigorous of adults. 
END OF VOLUME II. 
