THE BRITISH FOSSIL BRACHIOPODA. 263 



depression between them. Ventral valve rather deeper or more convex than the dorsal 

 one, with a mesial rounded rib, commencing at about half the length of the valve, and 

 extending to the front with a concave depression or rounded groove on either side ; beak 

 incurved and truncated by a circular foramen coming quite close to the umbo of the 

 dorsal valve. 



Length 16, breadth 15, depth 10 lines. 



Obs. — In my ' Oolitic Monograph ' (p. 54, and in PL XIII) I described and figured 

 Sowerby's types of Terebratida globata that had been lent me for that purpose by J. de 

 C. Sowerby, my fig. 2 being taken from the type figured in tab. 436, fig. 1, of the 

 ' Mineral Conchology.' At that period, as stated at p. 136 of my ' Jurassic Supple- 

 ment/ I had (I believe wrongly) included in Sowerby's species some allied forms, which 

 have been since then removed. Thus of my fig. 4 Oppel created his T. Euclesi, and 

 for fig. 7 he proposed his T. Fleischeri. He left, however, my fig. 6 among the forms 

 of T. globata, and that specimen is referable to the species under description. At p. 135 

 of my ' Jurassic Supplement ' I included the shell under description and T. Fleischeri 

 as varieties of T. globata, and of this the Birdlipensis, Walker, may be another 

 variation in shape ; but I was clearly wrong when I included Sowerby's T. bullata among 

 the varieties of T globata, this last being a Terebratida, while bullata is a Waldheimia. 

 Professor E. Deslongchamps, in his ' Brachiopodes Jurassiques,' devotes four whole plates 

 to figures of form-varieties of Sowerby's T. globata, and includes among them the 

 shell under description, as I had previously done. 



At p. 14 (1882) of his paper on the Brachiopoda from the Inferior Oolite of Dorset 

 and a portion of Somerset, Mr. S. S. Buckman refers the large form under description to 

 the Terebratula dorsoplana of Waagen (' Geog. Palaeont. Beitriige,' pi. xxxi, fig. 7, 

 1S67), but this identification seems to be uncertain, Waagen's shell being so very much 

 smaller, and more oval. 



The biplicated Terebratula, as a rule, are most puzzling and difficult to separate into 

 species, and it is quite clear to me that many Cretaceous and Jurassic so-termed species 

 have been, as it were, created out of mere modifications in shape of a very variable species. 



It may, however, be desirable to separate the shell under description from T. globata, 

 and as the large form under description, and T. Fleischeri, and the var. Birdlipensis, are 

 in every probability mere modifications in shape, they might all be classed; under the 

 name of T. Fleischeri, although this last name was applied by Oppel only to the elon- 

 gated modification of the broader form. 



Mr. S. S. Buckman, in his paper above referred to, states that the form under descrip- 

 tion is intermediate in shape to T. infraoolitica and T. perovalis. It was obtained 

 by Mr. S. S. Buckman from the Inferior Oolite near Sherborne, Dorset, and is 

 abundant at Birdlip and other places in the neighbourhood of Cheltenham. 



