ANNIVERSARY ADDRESS OF THE PRESIDENT. l6l 



The Tarannon species are Favosites asper, F. Jibrosus, F. gotlilan- 

 dicus, Petraia bina, and P. subduplicata. The four Denbighshire-grit 

 species are also Favosites aspera and F. Jibrosus, Petraia subduplicata 

 and Syringopora serpens. The upper member of the Lower Wenlock 

 (the Woolhope beds) yields 16 genera and 26 species, most equally 

 distributed generically. The North-Welsh Wenlocks yield 7 genera 

 and 11 species, and the South- Wales beds 10 genera and 18 

 species ; Scotland 8 genera and 11 species; and Ireland 14 genera 

 and 23 species. 



We must not forget that 14 genera and 22 species came from the 

 Llandovery rocks, and 18 pass to the Ludlow group, 13 of which 

 were also Llandovery ; thus 41 species are peculiarly Wenlock. 



Echinodermata. — As compared with the Upper Llandovery, with 

 only 5 genera and 5 species, and the Lower Llandovery only 2 

 species, the Wenlock sea must have been highly favourable to the 

 development of the Echinodermata ; no greater development of life 

 is known in any formation, for 60 of the 68 known species of 

 Echinodermata were new appearances in the British area. Many 

 are American ; 65 of the 68 are Wenlock Limestone ; no species is 

 known in Scotland, and only 1 in Ireland (Actinocrinus Wynnei, 

 Baily) ; only 1 species occurs in N". Wales in the Tarannon Shale 

 (Actinocrinus pulcher), and only 2 in the Woolhope (Eucalyptocrinus 

 poly dactyl us, M'Coy, and Pisocrinus pilula, De Kon.). 



We should expect that out of so large a fauna many species would 

 pass to the higher divisions of the Tipper Silurian, but only 4 genera 

 and 6 species pass to the Lower Ludlow. These are of the Crinoidea, 

 Actinocrinus pulcher, IcJithyocrinus pyriformis, and Icliiliyocrinus 

 JSP Coy anus ; of the Cystidea, Pseudocrinites magnijictis, P. quadrifas- 

 ciatus; and of the Asteroidea, Rlwphalocoma pyrotechnica. Icliiliyo- 

 crinus pyriformis is the only species occurring in the Aymestry 

 Limestone ; the Upper Ludlow only holds 1 species in common with 

 the Wenlock, the long-lived Actinocrinus pidcher. jSTo less than 20 

 new Echinodermal genera made their appearance in the Wenlock 

 sea, and 17 of them are confined to the Wenlock rocks ; the 4 genera 

 that pass to the Ludlow are Ichthyocrinus, Taxocrinus, Pseudocri- 

 nites, and Hhoplialocoma. This marked, sudden, and important 

 addition to the 3 orders of the Echinodermata can only be explained 

 upon the theory of migration from some prolific area ; whence it is 

 most difficult to suggest : but looking at the great generic and specific 

 development of the Crinoidea, Cystidea, &c. in N". America, and 

 the great resemblance, if not identity, of the faunas in the two 

 areas, would lead one to surmise that it was from the west rather 

 than from Europe that the Wenlock sea derived these Echino- 

 dermata. 



Annelida. — No other British Palaeozoic strata possess so many 

 species of Annelida; they number 35. The Upper Llandovery 

 possesses only 4 species, the Lower Llandovery 3, the Caradoc 16, 

 the Llandeilo 3, and Ludlow 17 species. 



This exuberance in the Wenlock strata is due to the researches of 



