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these animals are principally Rats, Beetles of various species, 
Bats and Crustaceans. Now I need hardly remind you, that 
although Bats and Beetles were once popularly supposed to 
be blind, it was only a vulgar delusion, and consequently the 
connection of these blind animals with the outer world 
becomes of extreme interest, in connection with Darwin’s 
theories as to the origin of species. His idea is that their 
ancestors wandered into these caverns in remote ages, that 
generation after generation was born and died without ever 
seeing light, so that the disuse of the organs of sight grad- 
ually led to their entire suppression, and this seems the more 
teasonable because one kind of rat was discovered, which 
though quite blind in the daylight, had eyes which were 
enormously developed and with which it could very probably 
see in the dark, while others had the optic nerve developed, 
though there was no vestige of external eye, and some of the 
beetles had their antennz enormously developed, as though 
to compensate for the loss of vision. The whole theory of 
the origin of species is one of enthralling interest. We all 
know that many animals existed in remote ages, which have 
no representatives now; but we scarcely reflect that in this 
our day species are dying off the face of the earth, several 
even have become extinct during the last 20 years, and Gosse 
estimates the loss in this way at no less than one species for 
every year. Thus it would appear that species have their 
allotted time for existence, just as individuals have theirs,— 
thus a Fly may have a span of life for a few days, a Raven or 
an Elephant of almost centuries—so the species of Irish Elk, 
or the species of the Mastodon may have reached their allotted 
span in the Tertiary Era; whereas that of the Dodo, the 
Great Auk, &c. may have expired only recently, and that of 
the Wolf, Beaver, &c. may be quickly approaching. The 
question then arises are fresh species being created? Are 
some of our newly discovered animals really only newly 
created ? We know that with individuals the death-rate 
is pretty nearly counterbalanced by births. Does this law 
hold good with species ? How many are and have been for 
ages extinct? There was the huge Dinotherium that wan- 
dered in the half-drained Swiss valleys and in the swamps of 
Germany, a monster larger than the largest Elephant, a body zo 
feet long and legs 10 feet high; a head something like that of 
