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BRITISH DEVONIAN BRACHIOPODA. 



and each valve was ornamented with from thirty-two to thirty-four large simple radiating 

 ribs, of which eight or nine formed a slightly elevated mesial fold. 



The dimensions of the most complete internal cast I have yet seen measured two 

 inches four lines in length, by two inches eleven lines in width. It is larger than any 

 other Devonian Rhynchonella with which I am at present acquainted, and approaches to 

 Mh. pleioplena from the Oriskany Sandstone of the United States, but the ribs are not so 

 large in this last as in the British species. 



Rhynchonella pleurodon, Phillips. PI. XIII, figs. 12, 13. 



Terebratula pleurodon, Phillips. Geol. of York., vol. ii, p. 222, pi. xii, figs. 25—30 



(but not 16), 1836. 



— — Ibid. Pal. Foss. of Devon, &c, p. 86, pi. xxxv, fig. 



155, 1841. 



Rhynchonella — Dav. Mon. British Carb. Brach., vol. ii, p. 101, pi. xxiii, 



figs. 1 — 15, &c. 



This species having already been fully described in another portion of the present 

 work, all we need mention is that the shell occurs in great abundance in the Marwood and 

 Pilton " Upper Devonian" beds at Marwood, Baggy Point, Barnstaple, Braunton, &c, in 

 North Devon, as well as in those of Petherwin and Landlake, in Cornwall. Some speci- 

 mens have also been found in the Middle Devonian limestone of Woolborough quarry, 

 near Newton Abbot. 



Rhynchonella reniformis, Sowerby. PI. XIII, figs. 6, 7. 



Terebratula reniformis, Sow. Min. Con., pi. ccccxcvi, figs. 1 — 4, 1825. 



— — Phillips. Pal. Foss. of Devon, &c, p. 88, pi. xxxv, fig. 



157, 1841. 



Rhtnchonella — Dav. Mon. Carb. Brach., p. 90, pi. xix, figs. 1 — 7. 



A complete description of this species will be found in the second volume of the 

 present work. I can discover no difference between the Carboniferous and the Devonian 

 specimens. In Devonshire it occurs in the Middle Devonian limestone of Lummaton, 

 near Torquay, as well as at Woolborough quarry, near Newton Abbot. 



Terebratula subdentata, Phillips (Pal. Foss. of Devon, PI. 35, fig. 164), is drawn 

 from an imperfect specimen of what I take to be an example of Bh. reniformis. Professor 

 Phillips states that Sowerby's figure of Atrypa subdentata represents a smaller specimen, 

 but that he is not at all in doubt as to its identity with the one he has described and 

 illustrated from the Upper Devonian of Petherwin. I have not, however, been able to 



