389 
must have been introduced in some abrupt manner, and that their variations 
have been within narrow limits and not progressive. This is the more 
remarkable, since great changes of level and of climate have occurred, and 
many species have been obliged to change their geographical distribution, 
- but have not been forced to vary more widely than in the Post-pliocene 
period itself. 
Pacts of this kind will attract little attention in comparison with the bold 
and attractive speculations of men who can launch their opinions from the 
vantage-ground of London journals ; but their gradual accumulation must 
some day sweep away the fabric of evolution, and restore our English science 
to the domain of common sense and sound induction. Fortunately also, 
there are workers in this field beyond the limits of the English-speaking 
world. As an eminent example, we may refer to Joachim Barrande, the 
illustrious palaeontologist of Bohemia, and the greatest authority on the 
wonderful fauna of his own primordial rocks. In his recent memoir on those 
ancient and 'curious crustaceans, the Trjlobites, published in advance of the 
supplement to vol. i. of the Silurian System of Bohemia, he deals a most 
damaging blow at the theory of evolution, showing conclusively that no such 
progressive development is reconcilable with the facts presented by the 
primordial fauna. The Trilobites are very well adapted to such an investi- 
gation. They constitute a well-marked group of animals trenchantly sepa- 
rated from all others. They extend through the whole enormous length of 
the Palaeozoic period, and are represented by numerous genera and species. 
They ceased altogether at an early period of the earth’s geological history, so 
that their account with nature has been closed, and we are in a condition to 
sum it up and strike the balance Qf profit and loss. Barrande, in an elaborate 
essay of 282 pages, brings to bear on the history of these creatures his whole 
vast stores of information, in a manner most conclusive in its refutation of 
theories of progressive development. 
It would be. impossible here to give an adequate summary of his facts and 
reasoning. A mere example must. suffice. In the earlier part of the memoir 
he takes up the modifications of the head, the thorax, and the pygidium or 
tail-piece of the Trilobites, in geological time, showing that numerous and 
remarkable as these modifications are in structure, in form, and in ornamen- 
tation, no law of development can be traced in them. For example, in the 
•number of segments or joints of the thorax we find some Trilobites with 
only one to four segments, others with as many as fourteen to twenty-six, 
while a great many species have medium or intervening numbers. Now in 
the early primordial fauna the prevalent Trilobites are at the extremes, some 
with very few segments, -as Agnostus; others with very many, as Paradoxides. 
The genera with the medium segments are more characteristic of the later 
faunas. There is thus no progression. If the evolutionist holds that the 
few-jointed forms are embryonic, or more like to the young of the others, 
then on his theory they should have precedence, but they are contemporary 
with forms having the greatest number of joints, and Barrande shows that 
