A.NNIVEESABX ADDRESS OF THE PRESIDENT. 



167 



( Euomphalus fureatus). Ireland yields 4 genera and 5 species 

 {Murehisonia articulata, M. Lloydii, Euomphalus alatus, Cyclonema 

 corallii, and Acroculia haliotis). We must remember that 5 genera 

 and 6 species range from the Upper Llandovery ; these are Euom- 

 phalus alatus, Sow., E. fureatus, Sow., E. sculptus, Sow., HolopeUa 

 obsoleta, Loxonema sinuosa, Sow., and Murehisonia articulata, Sow., 2 

 of the same occurring in the Caradoc, namely — Euomphalus alatus, 

 Sow., E. sculptus, Sow., and probably Tu rbo tritorquatus, IL'Coy; and 

 o of these same 6 range to the Ludlow. Only 17 species out of the 

 27 strictly belong to the Wenlock rocks proper. At present we 

 know of no species other than those in the division Holostomata 

 in the Silurian rocks. Eunema is the only new genus that appeared 

 in this formation ; E. eirrhosum is a South- Wales species. 



Pteropoda. — Only 3 species, Conularia Soiverbyii, Defr., Tlieca 

 anceps, Salt., and T. Forbesii, Sharpe, have as yet appeared in the 

 Wenlock group ; none of the 3 occurs in the Tarannon Shale, in the 

 "Woolhope beds, or in Ireland. Theca Forbesii has been found in 

 the Denbighshire Grits and Wenlock Limestone, and passes upwards 

 to the Upper Ludlow. T. anceps is here Wenloek only, but is a Cara- 

 doc species also. Conularia Soiverbyi first appeared in the Caradoc, 

 and, with the exception of the Upper Llandovery, is present in all 

 horizons up to the top of the Upper Ludlow ; it also occurs in the 

 Scotch beds. The only form of Thecosomatous Pteropod that trans- 

 gresses the Silurian rocks is Conularia, which is Devonian and 

 Carboniferous ; but in Britain Conularia has not occurred in the 

 Devonian series, although its associate, Bellerophon, is represented by 

 5 British Devonian forms, 2 occurring in the Lower, 1 in the 

 ^Middle, and 1 in the Upper Devonian. Conularia Sowerbyi and 

 Theca Forbesii both pass to the Upper Ludlow. 



Heteropoda. — This pelagic order is well represented in the Wen- 

 lock beds through Ecculiomphalus l<:evis and 7 species of Bellerophon ; 

 but no species is confined to or specifically characteristic of the 

 Wenlock beds. All had previously occurred either in the Caradoc 

 or Llandovery rocks. Ecculiomphalus Icevis, Bellerophon trilobatus, 

 and B. carinatus range into the Upper Ludlow beds ; none occurs in 

 the Tarannon Shale ; 3 species are known in the Denbighshire Grits 

 (Bellerophon trilobatus, B. expansus, and B. carinatus), and 3 in the 

 Woolhope beds (B. bilobatus, B. dilatatus, and B. trilobatus). In 

 the Wenlock Limestone we know of 4 species of Bellerophon and 

 Ecculiomphalus Icevis. B. dilatatus is the only form known in 

 Ireland ; and Scotland yields none. The 3 species passing up or 

 ranging into the Ludlow series are Ecculiomphalus Icevis, Bellerophon 

 trilobatus, and B. subdecussatus ; there are none in the Aymestry 

 Limestone. 



Cephaxopoda. — 5 genera and 30 species of the order Tetra- 

 branchiata, illustrating the jN"autilida3 and Orthoceratidee, are known 

 in the Wenlock rocks : all but 3 species are represented in the Wen- 

 lock Limestone and Shale ; these 3 are Woolhope species (Actinoceras 

 baccaturn, H. AToodw., Lituites comu-arietis, Sow., and Orthoceras coni- 

 cum, Sow.). Actinoceras baccaturn is essentially a Woolhope species, 



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