348 BRACHIOPODA OF THE 



20. Strophomena Vicaryi, Dav. B. S. Sup., PI. XXXIX, fig. 8. 



Strophomena Vicaryi, Dav. Quart. Journ. Geol. Soc, vol. xxvi, pi. vi, figs. G, 7, 1869. 



Shell transversely semicircular, regularly convex, with expanded angular extremities ; 

 hinge-line straight and long, with closely set slanting stria? ; area narrow, fissure 

 triangular; muscular impressions divided by a raised mesial ridge, external surface 

 marked by numerous thread-like strise, two or three finer ones being placed between each 

 pair of the larger striae; dorsal valve not known. 

 Length 8, breadth 11 lines. 



Obs. — Of this species we are at present acquainted with one valve only ; consequently 

 a complete description of the shell cannot be drawn up. The shape of the muscular 

 impressions in the ventral valve differs from those seen in S. Edgelliana. Mr. Salter 

 also expressed the opinion that the two are specifically distinct. It has been found by 

 Mr. Vicary in company with St. Mheridgii and Rh. ovalis, and is, no doubt, a Devonian 

 species. 



21. Strophomena Rouaulti, Dav. B. S. Sup., PI. XXXIX, fig. 9. 



Strophomena Rouaulti, Dav. Quart. Journ. G-eol. Soc, vol. xxvi, pl.vi, figs. 8, 9, 1869. 



Shell semicircular, slightly wider than long ; hinge-line straight, a little less than the 

 width of the shell : ventral valve very moderately convex, with a narrow area and open 

 fissure ; dorsal valve almost flat or very slightly concave. Exterior finely striated. In 

 the interior of the ventral valve a small hinge-tooth is situated on each side of the base 

 of the fissure, while the muscular scars form a large saucer-shaped depression, laterally 

 margined by a slightly elevated ridge. In the interior of the dorsal valve a wide raised 

 border surrounds the shell ; hinge-area linear. The cardinal process is composed of two 

 testaceous projections, under which are located two elongated, parallel muscular impres- 

 sions, surrounded by a narrow elevated ridge, and separated along the middle by a rather 

 wide interspace. 



Length 10, width 11 lines. 



Obs. — This species appears to be rare, only a few internal casts of the two valves 

 having been seen by Mr. Vicary in the Budleigh-Salterton pebbles. As no other 

 Brachiopod has been found associated with it in the same pebble, I cannot say 

 positively whether the species is Devonian or Silurian, but I believe it belongs to the first- 

 named formation. The shape of its muscular impressions seem to distinguish it from the 

 other forms of the genus that occur in the locality. 



