XT PHENOMENA OF ORGANIC NATURE 355 
Every fish that we find in the strata—to which I 
have been referring—can be identified and placed 
‘in one of the orders which exist at the present day. 
There is not known to be a single ordinal form 
of insect extinct. There are only two orders 
extinct among the Crustacea. There is not known 
to be an extinct order of these creatures, the 
parasitic and other worms ; but there are two, not 
to say three, absolutely extinct orders of this 
class, the Echinodermata ; out of all the orders of 
the Celenterata and Protozoa only one, iy Rugose 
Corals, 
So that, you see, out of somewhere about 120 
orders of animals, taking them altogether, you 
will not, at the outside estimate, find above ten 
or a dozen extinct. Summing up all the order of 
animals which have left remains behind them, 
you will not find above ten or a dozen which 
cannot be arranged with those of the present day ; 
that is to say, that the difference does not amount 
to much more than ten per cent.: and the 
proportion of extinct orders of plants is still 
smaller. I think that that is a very astounding 
a most astonishing fact: seeing the enormous 
epochs of time which have elapsed during the 
constitution of the surface of the earth as it at 
present exists, it is, indeed, a most astounding 
thing that the proportion of extinct ordinal types 
Should be so exceedingly small. 
But now, there is another point of view in which 
AA2 
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