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BRITISH DEVONIAN BRACHIOPODA. 



visionally at least) the distinctive denomination of rliomboidea until a large number of 

 Devonian and Carboniferous specimens can be compared. 



Camaropkoria rhomboidea occurs in the Middle Devonian limestone at Barton and 

 Iiiimmaton, near Torquay ; also in that of Woolborough, near Newton Abbot. On the 

 Continent it has been found at Gerolstein, in the Eifel, and where it has attained even 

 larger proportions than in Great Britain. 



Genus — Pentamerus, Sowcrby. 



Pentamerus brevirostris, Phillips (sp.). PI. XV, figs. 1 — 14. 



Stringocephalus brevirostris, Phillips. Pal. Foss. of Cornwall, Devon, and West 



Somerset, p. 80, pi. xxxii, fig. 143, 1841. 

 Terebratula (Atrypa) cassidea, Phillips (not of Dalmaii) ed. p. 83, pi. xxxiv, 



fig. 148, 1841. 



Pentamerus brevirostris, M'Coy. British Palaeozoic Fossils, p. 384, 1852. 



— globus (Bronn, in Collect), Schnur, in Palseontograpbica, vol. iii, p. 197, 



tab. xxxi, fig. 4. 



brevirostris, Geinitz. Grauwackenform. in Sachsen, vol.ii, p. 59, tab. 

 xv, figs. 1-3. 



— — Sandberger. Die Bracbiopoden Rheiniscben Scbicbten- 



systems in Nassau, p. 48, pi. xxxi, fig. 6, *• 



— globus, Sandberger. Ibid., p. 48, pi. xxxiv, fig. 1 . 



Spec. Char. Very variable in shape ; sub-orbicular, nearly circular, or broad -ovate, 

 usually longer than wide, and more or less globose. Dorsal valve moderately and evenly 

 convex, with or without a slight rounded mesial elevation, or more or less depressed along 

 the middle in the shape of a sinus, which is either entirely smooth or marked with two or 

 three longitudinal rounded ribs, which commencing at about the middle of the shell 

 extend to the front. Ventral valve gibbous, evenly convex, or presenting a slightly 

 elevated mesial fold ornamented with four or five longitudinal ribs. Beak obtuse, 

 incurved ; fissure triangular. In the interior of the ventral valve the dental plates 

 converge and form a small trough-like chamber supported on a median septum, while in 

 the dorsal valve there exists a long narrow trough-like process supported likewise by a 

 single low septum. Two specimens measured — 



Length 1 inch 11 lines, width 1 inch 7 lines, depth 1 inch 2 lines. 

 1 fi 17 1 ^ 



)■> )> 113 33 A 33 ' 33 } 3} - 1 33 W j, 



Obs. After having assembled and studied a great many specimens of the shell under 

 description, I became convinced of its extreme variability as well as of the necessity of 

 uniting under the single name of " brevirostris" several so-termed species which had been 

 fabricated out of some of its variations in shape. Prof. M'Coy has shown that Phillips's 



