1 873.] The Evolution Theory. 365 



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 reconcileable with the facts presented by the primordial 

 fauna. The Trilobites are very well adapted to such an 

 investigation. They constitute a well marked group of 

 animals trenchantly separated 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 

 of 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 con- 

 clusive in its refutation of theories of progressive develop- 

 ment. 



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 modifica- 

 tions 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 ornamentation, 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 Para- 

 doxides. The genera with the medium segments are more 

 characteristic of the later faunas. There is thus no progres- 

 sion. 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 these last cannot be held to 

 be less perfect than those with the medium numbers. Fur- 

 ther, as Barrande well shows, on the principle of survival 

 of the fittest, the species with the medium number of joints 

 are best fitted for the struggle of existence. But in that 

 case the primordial Trilobites made a great mistake in pass- 

 ing at once from the few to the many segmented stage, or 

 vice versa, and omitting the really profitable condition which 

 lay between. In subsequent times they were thus obliged 



vol. in. (n.s.) 3 b 



