50 BRITISH DEVONIAN BRACHIOPODA. 



moderately convex, with a prominent angular fold ; ventral valve pyramidal, deeper than 

 the opposite one ; sinus angular, commencing at the extremity of the beak and extending 

 to the front ; area large, flat, triangular ; fissure narrow, entirely arched over by a pseudo- 

 deltidium. Each valve is ornamented by from twelve to twenty small angular ribs, the 

 surface being likewise traversed by numerous concentric lines of growth. 



Length 4, width 8, depth 5 lines. 



06s. I am much puzzled how to deal with this shell, for although closely connected to, 

 and probably nothing more than a modification in shape or variety of, Cyrtina heteroclita, 

 it presents certain differences which might lead one to imagine it almost a distinct species. 

 Indeed, Phillips has described and figured it as a small form of the Carboniferous Spirifera 

 ct/spidata ; but from this it is not only specifically but also generically distinct, for its 

 internal dispositions agree with those we have already described for Cyrtina heteroclita. 

 Some specimens also appear to connect this variety with the typical forms of the species. 



It may, therefore, be better to provisionally consider it a variety of C. heteroclita, with 

 the distinctive denomination of " multiplicata " and I have figured a series of specimens 

 which will enable the reader to determine the question as he may think proper. The 

 variety here described has been found at Barton and Lummaton, near Torquay. 



Cyrtina Demarlii, Bouchard, MS. PI. IX, figs. 15 — 17. 



Spirifera subcontca, Phillips (not of Martin nor Sowerby). Pal. Foss. of Cornwall, 

 Devon, and West Somerset, p. 72, pi. xxix, fig. 126, 1841. 



Spec. Char. Shell small, wider than long ; hinge-line about as wide as the shell ; 

 dorsal valve semicircular, moderately convex ; ventral valve pyramidal, much deeper 

 than the opposite one, with a sinus of moderate depth, to which corresponds a biplicated 

 mesial fold in the opposite one ; about twelve simple ribs ornament the lateral portions of 

 each valve ; area large, triangular, situated at right angles to the general plane of the 

 dorsal valve ; fissure narrow, arched over by a pseudo-deltidium ; shell-structure 

 punctated. 



Length 3, width 4, depth 3 lines. Some specimens attained somewhat larger pro- 

 portions. 



06s. The longitudinal groove in the centre of the mesial fold serves to distinguish 

 this shell from C. heteroclita. The interior arrangements appear to be similar to those of 

 the last-named species, the median septum in the ventral valve being continued as far as 

 the under surface of the deltidium, while the dental converging plates are fixed to its sides. 

 Mr. Lee found two specimens of this small shell in the Middle Devonian Limestone of 

 Barton, near Torquay ; and it has been often collected by Mr. Bouchard and by myself at 

 Ferques (France). 



