52 BRITISH DEVONIAN BRACHIOPODA. 



twenty-two to twenty-four small, rounded, radiating ribs, of which a few are sometimes 

 bifurcated, with interspaces of almost equal breadth between them. The two or three 

 ribs which occupy the median groove are usually smaller than those which ornament the 

 lateral portions of the valves, the whole being crossed by numerous concentric lines of 

 growth. Beak of the ventral valve small, slightly incurved, and with a minute, circular 

 aperture under its angular extremity ; a small, flattened space existing, likewise, between 

 the beak-ridges and the hinge-line. Proportions variable : 



Length 6, width 5^, depth 1^ lines. 



Obs. This little shell, characteristic of the Middle Devonian beds of England and of 

 the Continent, was first discovered at Hope's Nose, near Torquay, and described by 

 Phillips as an Orthis. Subsequently, it was found by Professor Schnur in beds of a 

 similar age at Priim and Gerolstein, in the Eifel, where the shell appears not to be very 

 uncommon. Professor Schnur, however, gave to the Prussian specimen a new name, 

 Terebratula dividua, and figured at the same time a portion of the interior, to show two 

 vertically and spirally coiled lamellae, of which the extremities are directed towards the 

 bottom of the dorsal valve. This species is, therefore, not an Orthis, as was supposed by 

 Phillips, De Verneuil, and others, nor a Chonetes sarcinulata, as hinted by Professor Morris, 

 nor a Terebratula, as supposed by Schnur, but should find place in Dalman's genus 

 Atrypa, or Spirigerina of D'Orbigny. 



The Atrypa lens of Sowerby (PI. 21, fig. 3, of Murchison's 'Silurian System') 

 belongs to the genus Pentamerus. 



The careful examination I have made of the original types now preserved in the 

 Museum of the Geological Survey, as well as of some others found likewise at Hope's 

 Nose by Mr. Champernowne, and of a numerous suite of specimens sent to me from the 

 Eifel by Professor Schnur, leaves no uncertainty in the determination of this interesting 

 little species, or of its identity with Terebratula dividua of the last-named author. 



Atrypa lepida, Goldfuss (sp.). PL X, fig. 2. 



Terebratula lepida, If Archiac and De Verneuil. Description of the Fossils of the Older 



Deposits of the Rhenish Provinces, Trans, of the Geol. Soc, 2nd 



series, vol. vi, p. 368, pi. xxxv, fig. 2. 



— — A. Roemer. Die Versteinerungen des Harzgebirges, pi. xii, fig. 22, 



1843. 



Spirigerina — D'Orbigny. Prodrome de Pal6ontologie Stratigraphique, vol. i, p. 100, 



1849. 

 Terebratula — Schnur, in Dunker und Von Meyer's Palseontographica, vol. iii, p. 180, 

 tab. xxiv, fig. 1, 1853. 



Spec. Char. Shell very small, longitudinally oval, or circular ; ventral valve ventri- 

 cose, convex, and deep, with a shallow median groove and three feebly projecting 

 rounded ribs on each side of the lateral portions of the valve ; beak exceedingly small, 



