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BRITISH DEVONIAN BRACHIOPODA. 



another variation in shape, wherein the ribs are larger than in typical specimens of the 

 species under description. The number of ribs is very variable in some specimens, as 

 many as eighty may be counted round the margin, and of which twenty or twenty-two 

 compose the mesial fold and sinus. Professor M'Coy observes, that " the margins are 

 much sharper and more angular than in the Silurian Bh. Wilsoni, and the ribs simple ; 

 another difference is the small size at which the deflection of the margin begins in that 

 species ; there is no trace of it in the present one, which never acquires the great semi- 

 cylindrical extension of the Silurian shell." 



Bh. cuboides is a common Middle Devonian species, and occurs in the limestone of 

 Woolborough quarry, near Newton Abbot ; also in a yellow limestone at Ramsleugh 

 quarry, near Ogwell ; at Bradley, North Down; at Barton, Lummaton, and Hope's 

 Nose, near Torquay. It is also common in the Plymouth limestone, from which the 

 original examples of Bh. crenulata were obtained. On the Continent it occurs in the 

 Eifel, &c. 



Rhynchonella sphjsrica, Sow. PI. XIII, fig. 14. 



Atrypa sph^erica, Sow. Trans. Geol. Soc, 2nd ser., vol. v, pi. lvii, fig. 3, 1840. 



The original example on which this species has been established is now in the Museum 

 of the Geological Society ; and, although described and figured by Sowerby as from the 

 Devonian Limestone of Plymouth, has all the appearance of a Silurian specimen, which 

 by some chance may have become mixed up with other Devonian shells while in the 

 collection of the Rev. W. V. Hannah. Sowerby decribes his A. spharica as " spherical 

 or rather ovate, transverse, ventricose, plaited ; ribs of the front deeply sinuated, with five 

 elevated ribs ; beak small, adpressed, rather wider than long. Loc. Plymouth." It is 

 very doubtful whether this is in reality a British Devonian species. 



Rhynchonella primipilaris, von Buck. PI. XIV, figs. 4 — 6. 



Terebratula primipilaris, von Buck. Ueber Terebrateln, p. 68, tab. xi, fig. 29, a, b, 



1834. 



Atrypa primipilaris, Sow. Trans. Geol. Soc, 2nd series, vol. v, pi. lvii, figs. 5, 6. 

 Spirifer pentagonus, Sow. Encyclop. Metrop. 



Terebratula primipilaris, D'Archiac et de Verneuil. Desc. of the Fossils of the 



Older Rhenish Provinces ; Trans. Geol. Soc, 2nd series, 

 vol. vi, p. 392, read May 1840. 



— — Schnur, in Dunker und v. Meyer's Paheontographica, vol. 



ii, pi. xxvi, fig. 3. 



— angulosa, Schnur. Ibid., pi. xxv, fig. 5. 



