1(>2 . UK. F. J. NOETH OX [vol. lxxvi, 



5. On Syrixuuthyris Winchell, and Certain Carboniferous 

 Brachiopoda referred to SprRii-ERiXA D'Orbigny. By 

 Frederick: John North, D.Sc, F.G.S., Geological Depart- 

 ment, National Museum of Wales, Cardiff. (Read January 

 7th, 1920.) 



^Plates XI-XIIL] 



Contents. 



Page 

 Ii Introduction 162 



II. St/ringoth yris Winchell 165 



(a) History of Previous Research. 

 (6) The Characters of the Genus. 

 (r) The Type Species of Syringothyris. 



(d) The Subdivision of the Genus. 



(e) General Account of Syringothyris in Great Britain. 

 (/) Description of the British Species of Syringothyris- 



and their Mutations. 

 (g) Pre-Carboniferous History of Syringothyris. 



III. Notes upon Certain Species incorrectly referred to 



Syringothyris, and upon Species of Syringothyris 

 supposed to possess Plications upon the Fold and 

 Sinus. — The Genus Syringopleura 189 



IV. " Spiriferina' laminosa (M'Coy) : Tylothyris, gen. nor 194 



V. The Relation between Spiriferina and Syringothyris ... 206 



VI. Spiriferina D'Orbigny 208 



(a) Pre-Liassic Species referred to Spiriferina. 



(b) Punctospvrifer, gen. nov. 



(c) Carboniferous Species of Spiriferina. 



VII. Summary of Conclusions 221 



VIII. Bibliography 224 



I. Introduction. 



In this paper an attempt is made to remove the uncertainty which 

 has hitherto existed in the naming of the British species of 

 Syringothyris and of certain Carboniferous brachiopoda referred 

 to the genus Spiriferina. 



Recent zonal work on the Carboniferous Limestone has demon- 

 strated the desirability of (1) a more accurate knowledge of the 

 essential characters of Syringothyris, and (2) of distinguishing 

 names for the forms occurring at various horizons. In the case 

 of the Spiriferids with a lamellose surface-ornament, it has been 

 customary to refer them all to Spiriferina, because there was no 

 other genus for their reception — although it had long been recog- 

 nized that few, if any of them, really belonged to that genus. 



When this investigation was commenced some years ago, it was 

 intended to deal exhaustively with all the British Carboniferous 

 shells referred to Syringothyris and Spiriferina, together with 

 the relation of the latter to their pre-Carboniferous and post- 

 Carboniferous representatives, and a preliminary paper dealing 



