﻿Yol. 64.] HOMCEOMORPHY : ' SPIEIFEIl GLABEr! 29^ 



named are correctly identified. Certainly the large smooth Spirlfer 

 from the Permo-Carboniferous of Australia, which passes by this 

 name, has no connexion with any British species ; it is the smooth 

 development of Spirifer suhradiatus, Sowerby. 



The use of the generic name Martinia for various smooth 

 Spiriferids of the Devonian and Carboniferous becomes wholly 

 unjustifiable. Martinia thus used does not mark a genetic series, 

 as it ought ; but it simply denotes a stage of catagenetic development 

 at which several difi'erent stocks of Hpirifers arrive. On the other 

 hand, Reticularia does seem to indicate a fairly homogeneous series, 

 which shows various phases of decline of reticulation until partial, 

 or even complete, smoothness is attained. It is possible, however, 

 that there are two series now combined under Reticularia — one with 

 an extended area, of which R. ellijptica is the best representative ; 

 the other with a very short area, R. imbricata. Possibly there are 

 further structural differences to be found in these two series. The 

 first would be the true Reticularia. 



The distribution of the forms called '' Spirifer glaher' into the 

 various genetic series of which they are presumed to be the cata- 

 genetic developments involves the following consideration of some 

 of the generic names which have been given to Spirifers. The 

 allocation of species to these genera must in some cases be regarded 

 as requiring confirmation — in the shape of evidence of structural 

 details. 



Grenus Spirifer, Sowerby. 



(Type : Anomites striafus, Martin) 

 The striatus-tyipe of the Aperturati, Hall & Clarke. 

 Wide, with extended hinge-line; fine ribs medianly and laterally; 

 short dental plates. 



British species : — A. striatus ^ ; Spirifer attenuatus ; Sj?. clathratus ; 

 Sp. semicircularis ; ? Sp). princeps. 



American species : — Sp. condor, d'Orbigny ; Sp. cameratus, Morton 

 (Hall & Clarke), 



Indian species : — Sj:). moosaJcJiailensis, Davidson. 



Note. — Sp. princeps, M'Coy, 8p. tornacensis, de Koninek, Sp. cinctus, Kej- 

 serling, seem to form a group together, distinct from the striatus-^^ries and 

 having somewhat the appearance externally of Choristites ; but de Koninek 

 says that Sp. cinctus does not possess the strong dental plates of Sp. mosquensis. 



Genus Pusella, M^Coy. 

 (Type, as indicated by the name: Spirrferafusiformis, Phillips) 

 Wide ; extended hinge-lino ; ribs coarse laterally, tending to be 

 deficient medianly. 



The type is in the smooth stage when nearly all ribs have been lost. 

 British species :. — Sp. trigonalis ; Sp. grandicostata ; Sj). ornitho- 



^ The species left without authors' names are those taken from Davidson's 

 monograph on the British Carboniferous Brachiopoda ; that they correctly 

 interpret the original authors is not implied. 



