ANNIVERSARY ADDRESS OF THE PRESIDENT. 



123 



being more favourable for the support and distribution of certain 

 forms of life in one area than the other. The only 3 Scotch Llan- 

 deilo species known to me are IW.&nus Bowmanii, Salt., Salteria 

 involuta, Thorn., and S. primceva, Thorn. The 6 Irish species 

 are Acidaspis Jamesii, Ampyx mammillatus, Ogygia Porilockii, 

 Phacops truncato-caudatus, Calymene duplicata, and AEglina mirabilis. 

 The English forms are chiefly from the Shelve area ; and 8 out of 

 the 10 are South- Wales species. 



The following occupy and characterize definite areas; they are 

 single representatives of the genera named : — 





North 

 Wales. 



South 

 Wales. 



England 



. Scotland 



Ireland. 



Horoalonotus bisulcatus 



Agnostus M'Coyi 



Stygina Murchisonse 



Cheirurus Sedgwickii 



Acidaspis Jamesii 



* 

 1 



X- 



it 

 # 







* 



4 







1 



Thus 6 Llandeilo genera are illustrated by only 1 species each, 

 England and Scotland having no really marked or characteristic 

 form. Nevertheless there are important Llandeilo species which 

 are entirely restricted to that formation, not ranging either lower 

 or higher. The most important are : — 





North 

 Wales. 



South 

 Wales. 



England. 



Scotland. 



^ Ireland. 



Portlockii 



convexa 



Asaphus tyrannus 



Trinucleus Lloydii 



Edgelli 



Barrandia longifrons 



* 



it 



* 



* 



* 

 it 

 it 



it 



it 

 it 



* 



it 



it 



* 



9 



13 



6 



2 



1 



