36 BRITISH DEVONIAN BRACHIOPODA. 



05s. This large Spirifer occurs plentifully, but in a very distorted and compressed 

 condition, in the state of internal casts and impressions, in the Devonian grits of Looe, 

 in Cornwall. 



With such imperfect material at our command, it is hardly possible to arrive at an 

 exact specific identification ; but the less injured specimens resemble, by their general aspect 

 and character of ribs and fold, some similar casts of Sp. cultrijugatus I have received 

 from the Eifel district, and which were sent to me so named by Herr F. Roemer. In all 

 the figures published by Roemer, Schnur, and Sandberger, of Sp. cultrijugatus, the ribs on 

 the lateral portions of the shell are simple, and do not exceed about twenty on each valve ; 

 but in a specimen so named in my possession from the Palis of the Ohio, near Louisville, 

 in America, and which I received likewise, some years ago, from Herr F. Roemer, the 

 libs are small, in some places bifurcated, and numbering about thirty-four in each valve. 

 Some of our British examples bear, also, a certain resemblance to the Sjnrif. socialis of 

 Krantz, from the Devonian beds of Menzenberg ; l but it is very difficult to be certain 

 while comparing such imperfect distorted internal casts. 



Spirifera undifera, F. Roemer. PI. VII, figs. 1 — 10. 



Spikifer undiferus, F. Roemer. Itheinisch. Uebergangsgeb., p. 72, pi. vi, fig. 6, 1844. 



— — Schnur, in Dunker's Palaeontograpbica, vol. iii, p. 204, pi. xxxiv, 



fig. 3 a,b,c, d } 1853 . 



— — Sandberger. Die Brachiopoden Rheinischen Schichtensystems, 



p. 18, pi. xxxi, fig. 8, 1855. 



Spec. Char. Shell transversely or longitudinally oval ; hinge-line less than the width 

 of the shell ; cardinal angles rounded ; dorsal valve moderately convex ; mesial fold broad, 

 more or less sharply defined, of small elevation, and either slightly longitudinally depressed 

 or obtusely rounded. From sixteen to twenty-eight flattened or but slightly rounded ribs 

 ornament the surface of each valve. Ventral valve rather deeper than the opposite one ; 

 sinus broad, varying in depth, with one or two faintly marked longitudinal ribs on either 

 of its sides ; beak tapering, moderately produced and incurved ; area triangular, wider 

 than high; fissure partly arched over by a pseudo-deltidium. The surface of the valves is 

 regularly crossed by numerous fine, contiguous, concentric, serrated ridges, &c. Pro- 

 portions variable ; three specimens have measured — 

 Length 14, width 16, depth 10 lines. 



„ 20, „ 19, „ 13 „ 



" 15) ,, "20, ,, 11 ,, 



1 ' Ueber ein neues bei Menzenberg aufgeschlossenes Petrefakten-Lager in den Devonischen Schichten,' 

 tab. viii, fig. 3. 



