316 L. Agassiz on Animals in Geological Times. 
monograph of the Crustacea of Solenhofen by Count Minster, 
who has figured from that single locality more species than are 
known in the whole basin of the Mediterranean, excluding the mi- 
nute species which have not yet been sought for among the fossils. 
n earlier geological ages, during the deposition of the coal and 
other palzozoic rocks, the class of Crustacea presents a very dif- 
ferent character. ‘The gigantic Entomostraca and the extinct 
family of Trilobites take the place of the lobsters and crabs 0 
later periods. But paleontological works illustrating the fossils 
of Sweden, Russia, Bohemia, England and France, have made 
us acquainted with as great a variety of species of those families 
where within similar limits in the present time. 
The carcinological fauna of the whole Indian Ocean scarcely 
exceeds in variety or number of species that of Bohemia alone, 
as it is now known by the admirable investigations of Mr. 
de Barande. 
of Switzerland, the insects were as numerous and as diversi 
there as they are any where in our day, within similar bounda- 
ries. And the fragmentary information which we already om 
will 
justify the prophecy that insects will be found, some day 
other, even among paleozoic rocks older than the coal period. : 
