ORDOVICIAN BRACHIOPODA 141 



including a bilobed cardinal process, widely divergent socket ridges, a notothyrial 

 platform extending forward for less than one-third the length of the valve into a 

 median ridge possibly bifurcating anteriorly, and a pair of divergent transmuscle 

 septa. 



In respect of its ornamentation, profile and internal features, the brachial valve is 

 not only identifiable as Furcitella but also closely comparable with the type species 

 F. plicata from the Oranda Formation of Virginia (Cooper 1956 : 877), although on 

 the basis of impressions of only one valve specific identification would not be 

 reliable. 



MURINELLA Cooper 1956 



Murinella sp. 



(PI. 25, figs. 2, 3) 



The incomplete external and internal moulds of a pedicle valve (BB 35421a, b), 

 collected from the Meadowtown Beds exposed along the lane to Lower Ridge from 

 bench mark 754, Little Weston (Grid Ref. SO 293984), are best identified as the 

 strophomenid Murinella. The valve was 6-5 mm long and, when complete, must 

 have been semi-elliptical in outline with slightly acute cardinal angles, and evenly 

 convex with only a faintly developed median carina, giving a maximum depth 

 relative to length of about 10%. The ornamentation was finely costellate with 6 

 ribs per mm at 5 mm antero-medially of the umbo, crossed by fine fila and coarser 

 sporadically occurring growth lines. A pedicle foramen truncated the beak and the 

 relatively small teeth protruding dorsally of the apsacline interarea were supported 

 by short, widely divergent dental plates. The muscle scar was transversely elliptical, 

 extending forward for about one-third the length of the valve and about two-thirds 

 as long as wide. The various components of the muscle field are not identifiable 

 but there is a conspicuous median septum culminating in a point at the anterior 

 boundary of the scar and trailing forward beyond the boundary for a short distance 

 as a low ridge. 



The nature of the radial ornamentation, the even convexity of the valve and 

 especially the presence of a median septum in the muscle scar differentiate the valve 

 as belonging to Murinella. Indeed except for the greater extension of the median 

 septum beyond the anterior boundary of the muscle scar the valve compares closely 

 with the type species for the genus, M. partita from the Bromide Formation of 

 Oklahoma (Cooper 1956 : 848) : however, more material may demonstrate that the 

 Shropshire form is quite distinct. 



Subfamily RAFINESQUININAE Schuchert 1893 



RAFINESQUINA Hall & Clarke 1892 



Rafinesquina delicata sp. nov. 



(PL 25, figs. 6-13) 



Diagnosis. Piano- to gently concavo-convex Rafinesquina with a pedicle valve 

 8% as deep as long and a brachial valve 79% as long as wide, radial ornamentation 



