2U 



MR. P. LA.KE ON THE BRITISH 



[May 1896, 



III. Comparison with the Swedish and Bohemian Faunas. 1 



If we compare the British Silurian species of Acidaspis with 

 those from the same beds in Bohemia and Sweden, we arrive at 

 some interesting results. The following table includes all the 

 species which have yet been described from the Silurian of Sweden 2 

 and Britain, and also those from Bohemia which are nearly allied 

 to any of the Swedish or British forms. There are, however, 

 numerous Bohemian species besides these. 



In the table the species which are closely allied to each other are 

 placed upon the same horizontal line, so as to show the amount of 

 resemblance between the three faunas : — 



Sweden. 



A. bicuspis* 



A. crenata ; A. Barran- 



dei, Ang. 

 A. coronata(=A. Mark- 



lini). 

 A. centrina. 

 A. pectinata. 



A. cornuta.^ 



Britain. 



Bohemia. 



A, Brighti. 



A. Barrandei, F. & S. 



A. Grayi.\ 



A. vesiculosa, etc. 



A. crenata. 





A. coronata.\ 





A. erlnaceus. 





A. callipareos.f 

 A. deflexa. 





A. quinguespinosa.§ 

 A. Hughesi. 







Numerous other species. 



* Only a single fragment of A. bicuspis appears to have been discovered. 



1* I have had no opportunity of examining these species. 



j A. coronata occurs in Germany, but only in the boulders of the Glacial 

 deposits, and these have probably come from Sweden. 



§ The specimen of A. quinquespinosa described by Beyrich under the name 

 A. Brightii came, not from Bohemia, but from Ludlow. 



So far, then, as this comparison goes, two species from the 

 British Silurian are represented by closely allied forms in Bohemia, 

 and five in Sweden. There is but one Swedish species represented 

 in Bohemia, of which only a single specimen i3 known ; and, on 

 the other hand, there is only one which is not represented in Britain. 

 Lastly, there are more species of Acidaspis in the Silurian of 

 Bohemia than in the Silurian of Sweden and Britain put together. 



These results are suggestive, but they are no more. Until a 

 larger number of species has been examined, it would be rash to draw 



1 I have to thank Prof. Lindstrom for permission to examine the magnificent 

 series of trilobites in the Riksmuseum at Stockholm, and for much kind assist- 

 anceduring my stay in that city. 



2 See Prof. Lindstrom's ' List of the Fossil Faunas of Sweden,' edited by the 

 Palgeontological Department of the Swedish State Museum (Natural History), 

 pts. i. & ii. Stockholm, 1888. The two species A. centrina and A. cornuta from 

 the upp^r 'Brachiopod Schists' are included, since those beds seem to contain a 

 certain number of Llandovery forms. 



