ANNIVERSARY ADDRESS OF THE PRESIDENT. 



remaining 7 being from the Durness limestone of Scotland (they may- 

 be Arcnig). The Scotch species are Euomplialus matutinus, Hall, 

 Murchisonia angulocincta, Salt., ill. angustata, Hall, M. bellicincta, 

 Salt., M. gracilis, Hall, Ophileta compacta, Salt., and Pleurotomaria 

 thuli, Salt. Three of the 12 pass to the Carodoc. Euomphalus, 

 Cyclonema, and Murchisonia are new genera, and first appear in 

 the Llandeilo. 



Pteropoda. — Three species of Theca — T. cometoides, Uaily (Irish), 

 T. reversa, Salt., and T. caereesiensis, Hicks (from St. David's). No 

 species occurs in England, North Wales, or Scotland. 



Heteropoda. — Scotland possesses 5 of the 7 species known ; and 

 4 of the 5 are Maclurece. These are associated with the Gastero- 

 poda in the Durness limestone. Belleroplwn perturhatus is a North 

 and South Welsh species ; and B. bilobatus, English, North and South 

 Welsh also. Euomplialus scoticus is from the Ayrshire rocks. The 

 3 last-named species and Ecculiomplialus pass to the Caradoc. 



Cephalopoda. — Of the 3 genera and 7 species none occurs either 

 in North Wales or Ireland. The only English species is Orthoceras 

 Avelani ?, Salt., from the Shelve area (Shropshire) ; Endoceras eoum, 

 Edgell, is from South Wales. The remaining 5 of the 7 known 

 species are Scotch, including the singular genus Piloceras (P. in- 

 vaginatum) from the Durness limestone. 



The accompanying Table (p. 126) gives the following results. 

 The 12 zoological groups occurring in the Llandeilo rocks are re- 

 presented by 80 genera and 175 species, which are numerically 

 distributed as follows : — 



England .... 18 genera and 26 species. 



North Wales.. 30 „ „ 47 „ 



South Wales.. 47 „ „ 88 „ 



Scotland .... 31 „ „ 66 „ 



Ireland 31 „ „ 57 



38 genera and 73 species of the 175 pass to the Caradoc. It 

 will be seen that it is through the Hydrozoa, Crustacea, and Bra- 

 chiopoda that the community of species largely occurs between the 

 Llandeilo and Caradoc generically and specifically — through the 

 Hydrozoa 9 genera and 16 species, the Crustacea 9 genera and 

 17 species, and the Erachiopoda 7 genera and 23 species. The re- 

 maining passage numbers are seen in Table IX. 



