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BRITISH DEVONIAN BRACHIOPODA. 



which appears exceedingly like a small example of the Carboniferous P. fimbriatus, Sow., 

 or P. laxi-ynnus, M'Coy, but which may have got accidentally mixed up among the 

 Rev. W. V. Hennah's Plymouth specimens. The original example is now in the 

 collection of the Geol. Soc. ; but we will not include it without further proof in our list 

 of British Devonian species. A figure of the shell will be found in PI. XX of our 

 Monograph. 



Family— DISCINIDiE. 

 Gen us — D i s c i n a , Lama rck. 



DlSCINA NITIDA, PJlillijJS. PI. XX, figS. 9, 10. 



Oebicula nitida, Phillips. Geol. of York., vol. ii, p. 221, pi. ix, figs. 10—13, 1836. 

 Discina — JDav. A Mon. of British Carboniferous Brachiopoda, p. 197, pi. 

 xlviii, figs. 18—25, 18G3. 



Spec. Char. Shell marginally circular or elongated oval, the posterior portion being 

 rather narrower than the anterior one, Large or free valve limpet-like, the pointed apex 

 being situated at variable distances between the centre and the posterior margin : surface 

 covered with numerous small, irregular, concentric wrinkles or stria?. The smaller, or 

 lower valve is somewhat flattened, or slightly concave towards its anterior margin, with 

 an oval-shaped foramen, surrounded by an elevated, convex margin, which extends from 

 near the centre of the valve to a variable distance from the posterior edge. This valve 

 is likewise ornamented with numerous concentric ridges or wrinkles, with small, 

 flattened interspaces. Dimensions variable — 

 Length 8, width 7 lines. 



Obs. This species occurs in the Upper Devonian, Carboniferous, and Permian forma- 

 tions of Great Britain. It has been found in greenish shales, or silty bed, of the Marwood 

 group at Muddiford, about six or seven miles from Ilfracombe, on the Barnstaple road, 

 also at Sloly or Plaistow Mill quarry, parish of Shirwell. Mr. Salter has also found 

 a fine example in a dark grey limestone, which he attributes to the Marwood beds of West 

 Angle, south side ; this specimen can be seen in the Museum of the Geol. Survey. 



