46 BRITISH DEVONIAN BRACHIOPODA. 



Spirifera simplkx, Phillips. PL VI, figs. 18 — 22. 



Spirifera simplex, Phillips. Palaeozoic Fossils of Cornwall, Devon, and West Somerset, 



p. 71, pi. xxix, fig. 124, 1841. 

 Spirifer — Roemer. Die Versteinerungen des Harzgebirges, pi. iv, fig. 11. 



— — Sandberger. Die Brachiopoden des Rlieinischen Schichtensystems in 



Nassau, pi. xxxii, fig. 10, 1855. 



— — Quenstedt. Hand, der Petrefactenkunde, pi. xxxviii, fig. 22, 1851. 



Spec. Char. Obtusely pyramidal, wider than long ; hinge-line straight, slightly shorter 

 than the width of the shell. Ventral valve deep, pyramidal, and longitudinally divided by 

 a sinus, which commences at the extremity of the beak and extends to the front. Area 

 triangular, as wide as long, and situated at a right angle to the general level of the dorsal 

 valve ; fissure narrow, arched over by a psendo-deltidium. Dorsal valve semicircular, 

 evenly and uniformly convex, with or without a slight elevation near the front. Surface 

 smooth. Proportions variable. 



Length 14, width 18, depth 12 lines. 



Obs. This species is easily distinguishable from other British Devonian species. It 

 occurs in the Middle Devonian limestone of Woolboroiigh, near Newton Abbot, and has 

 also been found in limestone near Plymouth, in Devonshire. On the Continent it occurs 

 abundantly at Paffrath, near Cologne, in Nassau, the Hartz, &c. 



Sub-germs — Spiriferina, D'Orbigny. 

 Spirifeiiina cristata, Schloth. (sp.), var. PL VI, figs. 11 — 15. 



Terebhatulites ckistatus, Schlotheim. Beitr. z. Naturg. d. Verst. in Akademie der Wissen- 



schaften zu Miinehen, pi. i, fig. 3, 1816. 



Spirifera cristata, Dav. Men. British Permian Brachiopoda, p. 17; and Carboniferous 



Mon., pp. 38 and 226. 



Spec. Char. Shell transversely subrhomboidal ; valves almost equally convex ; hinge- 

 line as long as or slightly shorter than the width of the shell; cardinal angles acute or 

 slightly rounded ; ventral area triangular ; fissure partly arched over by a pseudo-deltidium ; 

 beak incurved. The mesial fold in the dorsal valve is usually formed of a single rib, 

 flattened along the middle, and to it corresponds a sinus in the opposite one. The remain- 

 ing portion of each valve is covered with from eight to twelve angular ribs, the surface 

 of the shell being also (in perfect specimens) intersected at close intervals by numerous 



