﻿96 



BRITISH DEVONIAN BRACIIIOPODA. 



? Chonetes minuta, Gold/. PI. XIX, figs. 10 — 12. 



Orthis minuta, Goldfuss, Von Buch., Abhandl. der Konigl. Akad. der Wissens. zu 

 Berlin, p. 68, 183G. 



— — Goldfuss. Von Buch., Mem. de la Soc. Geol. de France, vol. iv, p. 217, 



1840. 



— — d'Archiuc and De Yerneuil. Desc. of the Fossils of the Rhenish Pro- 



vinces. Trans. Geol. Soc, 2nd ser., vol. vi, pi. xxxvi, fig. 5, 1841. 

 Chonotes minuta, de Koninck. Mon. des genres Productus et Chonetes, p. 219, 

 pi. xx, fig. 18, 1847. 



Spec. Char. Sub-hemispherical, or transversely oval; hinge-line straight, shorter than 

 the width of the shell ; cardinal angles rounded ; ventral valve uniformly convex ; beak 

 small, incurved, and more or less conspicuous ; area narrow, but broader than that of the 

 dorsal valve, and divided in the middle by a small fissure arched over with a pseudo- 

 deltidium. Dorsal valve concave, and particularly so under the beak; area narrow. 

 Surface of both valves marked with from twenty-two to thirty distinct, radiating, rounded 

 ribs, separated by interspaces of rather less width. The valves are also crossed by 

 numerous concentric lines of growth. The ribs are simple, and rarely bifurcate or increase 

 in number by interpolation. Proportions variable ; two specimens measured — 

 Length 5, width 7 lines. 

 j> 5 ,, 6 ,, 



Obs. The nearest described species of Chonetes with which we can compare the shell 

 under description is the C. minuta of Goldfuss ; indeed, an example from Dartington was 

 very similar in shape and character to the one from the Eifel, which was described and 

 figured by M. de Verueuil. Some of our specimens were, however, a little more trans- 

 verse, but any one who has seen a number of individuals of any species of Chonetes will 

 be aware of the great variability to which it is liable. It differs, also, from C. Ilardrensis 

 by its fewer and comparatively stronger ribs, for a specimen of C. minuta on which I 

 counted about thirty ribs, one of C. Hardrensis, of about the same dimensions, would 

 number not less than seventy. 



C. minuta (if I am not mistaken in identifying our British specimens with that species) 

 occurs in the Middle Devonian Limestone of Dartington, near Totness, as well as at Hope's 

 Nose, near Torquay. On the Continent it occurs in the Devonian Limestone of 

 Blankenheim in the Eifel. 



