Central Bohemia, by Joachim Barrande." 311 



clature in their own language, both for the animals and the 

 rocks in which they are found. Some of them who have 

 been longest in his employment are not only able to catch 

 the most evanescent traces of the minutest embryos with the 

 microscope, but at once recognise any new or rare form in 

 the district where they are engaged. 



M. Barrande has thus been enabled to extend his re- 

 searches over a far wider range of localities, and to bring 

 together a greater number and variety of specimens than 

 would have been possible for an isolated individual. Some 

 of the results of this wholesale mode of collecting specimens 

 are not only curious, but of importance in the history of the 

 animals. Thus the Dalmanites socialis is one of the most 

 common trilobites in Bohemia. It is characteristic of the 

 quartzites of his stage D., some beds in the Drabow moun- 

 tains being quite full of fragments of it, which form often 

 nearly the entire surface of the rock. Yet they were only 

 fragments ; and it was some years before perfect specimens 

 of the whole animal were found in another locality. But 

 these were badly preserved, and though collected in hundreds 

 did not give the information on the structure of the animal 

 that was wanted. At length a new depository of them was 

 discovered in the Drabow mountains, with perfect, well-pre- 

 served specimens. In these, however, the body was always 

 extended, and a new locality had to be discovered before any 

 were found rolled up, as was the case with all of them it 

 furnished. Eight years had been spent in these researches, 

 and some thousand specimens of this Dalmanites had passed 

 through his hands, but all of adult individuals, when a new 

 locality enabled him to complete the history, and to trace 

 out the singular metamorphoses it undergoes, as represented 

 in the highly interesting series of figures in his twenty- sixth 

 plate. 



Ten years' researches were thus required to work out the 

 history of this single trilobite, and the same was true of 

 many others. A second result of this persevering diligence 

 was the great increase in new species which it often produced. 

 A quarry was sometimes wrought for several years without 

 adding a new form to his list, when all at once some novel 



