﻿f)4 



BRITISH DEVONIAN BRACHIOPODA. 



of Woolborongh quarry, near Newton Abbot, as well as in the limestone of Barton and 

 Lummaton, near Torquay. It has also been found at Partington, near Totness and 

 at Mount Wise, near Plymouth, &c. 



Rhynchonella triloba, Sowerby. PI. XII, figs. 1 — 7. 



Atrypa triloba, Sow. Trans. Geol. Soc, 2nd ser., vol. v, pi. lvi, fig. 14. 



— latissima, Sow. Ibid., pi. lvi, fig. 25 (not T. latissima of the Min. Con.). 



Spec. Char. Tetrahedral, rather wider than long, with rounded angles ; dorsal valve, 

 when adult, very gibbous and trilobed, the median lobe forming an elevated mesial fold. 

 Surface ornamented with numerous radiating ribs. Ventral valve convex, but much less 

 so than the opposite one, with a very wide concave sinus : lateral margins sigmoid, front 

 margin abruptly arched upwards into a sinus ; beak small, and so much incurved as to 

 conceal the foraminal aperture. Surface ornamented with numerous radiating angular 

 ribs. Proportions very variable : two specimens measured — 



Length 1 inch 9 lines, width 2 inches, depth, 1 inch 9 lines. 



1 „ 1 6 lines 8 



Obs. This is an exceedingly variable shell, being at times and especially up to a 

 certain age comparatively flattened, the trilobation of the valve being more often apparent 

 with age. Bh. triloba therefore passes through the same kind of variation as has already 

 been described in my ' Monograph of British Carboniferous Species/ with reference to Bh. 

 acuminata, but with this difference, that the surface of Bh. triloba is always covered with 

 radiating ribs, while these are the exception in Bh. acuminata. Some examples of the 

 shell under description bear resemblance to the Jurassic Bh. trilobata, but are neverthe- 

 less specifically different. Atrypa latissima, Sowerby, from the Middle Devonian lime- 

 stone, has the appearance of being nothing more than a compressed variation in shape of 

 Bh. triloba, but is very different from Bh. latissima of the Cretaceous formation. Bh. 

 triloba is a common shell in the Middle Devonian limestone of Woolborongh quarry, near 

 Newton Abbot. It occurs also at Barton, near Torquay ; and at Plymouth, from whence 

 Sowerby's figured specimens, now in the museum of the Geological Society, were obtained. 



Rhynchonella bifera, Phillips. PI. XII, figs. 10, 11. 



Terebratula bifera, Phillips. Palaeozoic Fossils of Cornwall, Devon, and West 

 Somerset, p. 84, pi. xxxiv, fig. 151, 1841. 



Spec. Char. Tetrahedral, wider than long : dorsal valve moderately convex and 

 trilobed, the central lobe being formed by the mesial fold, which commences to become 

 defined and moderately elevated towards the middle of the valve, and from whence it 



