I90I S. S. BUCKMAN— BRACHIOPODA 253 



The species is found in the Fullers' Earth Rock of 

 Nunney, near Frome, Somerset. Its date is, therefore, 

 presumably the hemera of Macrocephalites stibcontrachis. 



The specimen now figured is the one found by Mr 

 Wilson ; it is now in the collection of that keen Brachio- 

 podist, Mr J. W. D. Marshall,* who has kindly sent it to 

 me again, with another example, for the purpose of this 

 paper. 



7. (2) ZEILLERIA BICORNIS, S. Buckman. 



1878. Walheimia EMARGINATA, Davidson, Supple- 

 ment to Jurassic Brachiopoda, pi. xxiii., 

 fig. 7 only. 



Description : — Sub-pentagonal in outline, with a bilobate front margin. 

 Brachial valve flattish, pedicle valve sub-gibbous. Valves thickened 

 at margin, often considerably ; and the thickened bilobate portion often 

 protruded ; beak sub-elevated, well separated from umbo ; deltidial 

 plates exposed ; beak ridges defined, acute. 



CoDiparison : — Terebratula imitator is a remarkable 

 homoeomorph in another genus. Z. stLbcornuta is a 

 homoeomorph in the same genus. Both are isochronous 

 homoeomorphs, or nearly so. 



Distinction : — From Z. Wattoni, the bilobate front 

 margin. 



Genetic affinity : — It is a bilobate development of the 

 form of Z. Waltoni^\\\Q\\ lived during Garantiance hemera. 

 (There is more than one form called Z. Waltoni^. 



Localities and Strata : — Dorset: Bradford Abbas, Broad 

 Windsor, in the upper beds ; Louse Hill, near Halfway 

 House, above the Irony bed. Somerset : Crewkerne 

 Station, upper beds ; Milborne Wick, Garantiana beds. 



Date of existence : — Garantiance hemera-, perhaps later 

 also. 



* I would call attention to his most useful papers, " Notes on British Jurassic 

 Brachiopoda," Proc. Bristol Nat. Soc, Vol. viii., 1895-7. 



