Palaeozoic Bivalved EntoTtiostraca. 359 



5. BeyricMa Jonesiij Boll. 



Beyrichia Jonesii, E. Boll, 1856, Zeitschr. d. d. geol. Ges. vol. viii. p. 322, 



figs. 1 and 2, ; 1862^ Arcliiv Ver. Yr. Nat. Meklenbiirg, 16. Jahr. 



p. 134, fig. 8. 

 '^BeyricMa verrucosa, Kolmodiii, 1869, Syerig. Silur. Ostrac. p. 19, 



fig. 12. 

 F Beyrichia Jonesii, Kolinodiu, 1880, CEfv. K. Vet.-Akad. Fbrdhaudl. 



vol. xxxvi. p. 137. 



B. Jonesii has the middle lobe relatively small and pressed 

 more or less closel;^ against the inner side of one of the lobes. 

 The ventral union of the lobes, usually by a thin isthmus, is 

 variable in extent. Surface of the large lobes granulate or 

 tuberculate. The marginal rim well developed and radiate. 

 In Kolmodin's B. verrucosa^ which he regards as B. Jonesii^ 

 the front and hind lobes freely coalesce, and, together with 

 the margin, are tuberculated. In the latter feature this re- 

 sembles Boll's B. nodulosa, otherwise it resembles Boll's 

 fig. 2 (1856) and fig. 8 (1862). 



A specimen closely resembling fig. 1 of Boll's B. Jonesii 

 has been found by Dr. Holl in the Wenlock Limestone of 

 Eastnor Park, below the Herefordshire Beacon, on the west 

 side, near Malvern. 



6. Beyricliia admixta, sp. nov. (PL XII. fig, 5.) 

 Proportions : — L. 13. H. 7. 



These few, small, oblong valves (Smith Coll. no. 55.,, from 

 Woolhope) have three distinct subequal vertical lobes, "evenly 

 united below, and also the begirming or root of an obscure 

 supernumerary lobe, apparently a duplication of the gigot, 

 as if it w^ere to be divided vertically, but only a part of it 

 exposed. 



This form is closely allied, if not belonging, to the four- 

 ridged group {Plurijugatce) . It evidently requires a distinct 

 name ; admixta has reference to this intermediate character. 



7. Beyrichia lacunata, sp. nov. 

 (PI. XII. figs. 18, 19, 20.) 



-p .• /Figs. 18, 20: L. 12. 

 Proportions:|j..|jg/j^^^^^ H. 



H.6. 

 6. 



These oblong little valves vary in dimensions, outline, and 

 contour. Some are longer than others, and then have the ven- 

 tral margin somewhat incurved, instead of being straight or 



