ANNIVERSARY ADDRESS OE THE PRESIDENT. 



211 



Number of Species in the six Palaeozoic orders of the Crustacea 

 occurring in England, Scotland, and Ireland ; also in Belgium 

 and America. The two latter areas for comparison as before. 



Orders. 



England. 



Scotland. 



Ireland. 



Belgium. 



America. 





45 



68 



38 



21 



9 





18 



29 



14 



9 



11 





8 



1 



5 





2 





1 



2 







2 





1 



7 









Trilobita 



13 



7 



14 



15 



26 





86 



114 



71 



45 



50 



Brtozoa. — The Carboniferous Bryozoa as a group constitute by far 

 the largest series in any division of the Palaeozoic rocks. 77 species 

 range through the 3 lower horizons of the Carboniferous series, 74 

 belonging to the true Carboniferous Limestone, 28 to the Lower Lime- 

 stone Shales or Lower Limestones, and 4 to the Calciferous series ; not 

 a single species passes to or occurs in the Yoredale, Millstone Grit, or 

 either one of the three divisions of the Coal-measures. The whole 

 group essentially belongs to and characterizes the Calcareous rocks 

 and shales at the base of the formation ; the large genera are — 

 Ceriopora 5 species, Fenestella26, Glauconome (Acanthocladia) 8, and 

 Polypora 8. 20 other genera of great zoological value occur, but the 

 species are few in each genus (1 to 4). Actinostoma, Carinella, Dias- 

 topora, Goniocladia, Hemitrypa, Ptilopora, Bhabdomeson, Synocladia, 

 and Vinculdria are important genera in the Carboniferous rocks, 

 and distinctively determine the age of the beds in which they occur. 

 Be it remembered that none of the Palaeozoic genera live on or 

 extend into the Mesozoic period, and the Fenestellidae become 

 extinct in the Permian rocks. 24 genera and 77 species at present 

 represent the fauna of this division of the Molluscoida ; doubtless 

 the species will be much reduced through extended research and 

 critical examination*; bnt as Mr. Shrubsole is carrying on research 

 in the Fenestellidae, and Mr. Vine investigating the Diastoporidae, it 

 is better to give the census of the species as they now stand without 

 incomplete modification. Mr. Shrubsole's last paper is not yet pub- 

 lished ; I will therefore notice their distribution, subject to the 

 anticipated work of these two authors. 



Calciferous Sandstone. — Archceopora nexilis, Ceriopora similis, 

 Fenestella Morrisii, F. plebeia, F. tuberculato-carinata, and Glauco- 



* Vide the able papers by Mr. Shrubsole, F.G.S., and Mr. G. E. Vine in the 

 ' Quarterly Journal of the Geological Society,' vol. xxxvi. ; also Vine, ' Eeport of 

 the British Association,' 1880, " On the Carboniferous Polyzoa," for important 

 matter relative to the history and classification of the Polyzoa. 



