350 BRACHIOPODA OF THE 



Mr. Vicary found this single specimen associated with Rh. ovalis. The peculiar shape 

 of its area and the accompanying pits seem to distinguish it from other known forms of 

 the genus, although it is impossible to offer a complete description of its characters. 



24. Strophomena Etheridgii, Dav. B. S. Sup., PI. XXXIX, figs. 10, 11. 



Stkopiiomena Ethekidgii, Dav. Quart. Journ. Geo!. Soc, vol. xxvi, p. 85, pi. vi, 



figs. 10—12, 18G9. 



Semicircular, as wide as, or rather wider than long ; hinge-line a little shorter than the 

 width of the shell ; ventral valve very slightly convex ; area narrow ; muscular impressions 

 forming a large saucer-shaped depression, laterally margined by a slightly raised border, 

 and longitudinally divided along the middle by a narrow ridge. In the interior of the 

 ventral valve the hinge-area is linear, with a minute cardinal process in the centre ; under 

 this is situated a small oval-shaped depression, with another small pit on either side, 

 while beyond there may be seen the small hollow for the reception of the teeth of the 

 ventral valve. Under the three central depressions above described there exists a short 

 raised mesial ridge, broad at its origin, but becoming gradually attenuated as it approaches 

 its anterior termination ; between this and the hinge-line are seen two granular ovarian 

 elevations. The muscular impressions are indistinct. Exterior surface not known, in all 

 probability finely radiatedly striated. 

 Length 11, width 12 lines. 



Of this interesting species I have seen but two internal casts. It was found by Mr. 

 Vicary along with JS. Edgelliaiw, and is in all probability a Devonian species. 



25. Strophomena, sp. ? Dav., B. S. Sup., PL XXXIX, fig. 1 a } b. 



Semicircular, wider than long ; hinge-line straight ; ventral valve slightly convex, 

 covered with very fine, thread-like, radiating striae, with a shorter one between the larger 

 pair. 



Length 8, width 11 lines. 



On the internal cast of ventral valve the muscular impressions cover upwards of a 

 third of the breadth of the valve and half of its length. The area is narrow. In the 

 internal cast of dorsal valve there exists, under a very small cardinal process, a small pit 

 and two smaller lateral ones. A short median ridge extends from under cardinal process 

 to a little distance, and on cither side are situated the muscular impressions. 



