ANNIVERSARY ADDRESS OF THE PRESIDENT. 



Si 



Brachtopoda. — Lingulella, Obolella, and Orthis are the only 3 

 genera in the Lower Lingula-flags. The 5 species are Lingulella 

 Da visit and L.lepis (both ranging to the Arenig), L. ferruginect, 

 Obolella macidata, and Orthis sagittalis. The last named is also 

 Tremadoc. 



Lamellibranchtata. — None known below the Lower Tremadoc, 

 where 3 new genera and 12 species suddenly appear ; they will be 

 noticed under the Lower Tremadoc beds. 



Gasteropoda. — None occur beneath the Arenig rocks. 



Pteropoda. — Theca corrugata, Salt., and T. obtusa, Salt., are the 

 only 2 species that occur. The last named is confined to the Lower 

 Lingula-flags. 



Heteropoda. — None below the Middle Lingula-flags ; and the only 

 species occurring therein is Better oplion cambrensis, Belt. 



Cephalopoda. — None have yet appeared below the Upper Tremadoc, 

 where the oldest forms known occur. 



The fauna of the Lower Lingula-flags is expressed in the follow- 

 ing Table ; and it will be seen in the passage column that only 8 

 species pass to the Upper Lingula-flags. They are Agnostus prin- 

 ceps, A. trisectus, Anopolenus Salteri, Microdiscus punctatus, and 

 Paradoocides Hicksii, Lingullela Davisii, L. lepis, and Orthis sagittalis. 

 Only 2 species are believed to connect the Middle and Lower Lin- 

 gula-flags — Conocoryphe bucephala, Belt, and Lingidella Davisii, 

 M'Coy. Indeed the wbole fauna of the middle division only amounts 

 to 5 species — the two just named, and Kutorgina cingulata, Bill., 

 Lingida squamosa, Holl, and Better ophon cambrensis, Belt. 



Nine entire classes are unrepresented in the Lower Lingula-flags, 

 as shown in the Table. 



Table III. — Loiver Lingida- flags. 



Pass up 

 from 

 Menevian. 



Classes. 



Genera. 



Species. 



Pass to 

 Middle 

 Lingula- 

 flags. 



Pass to 

 Upper 

 Lingula- 

 flags. 





Plantse. 











i 

 i 





1 



1 









Hydrozoa. 













Actinozoa. 













Echinodermata. 













Annelida 



3 



3 







8 



1 4 





9 



25 



i 

 i 



4 

 5 





Bryozoa. 











3 

 3 





3 



5 



i 



3 





Lamellibranchiata. 













Gasteropoda. 











1 





1 



2 









Heteropoda. 













Cephalopoda. 











1 3 

 1 9 





17 



36 



2 



7 



