Brachiopoda from the Bokkcveld Beds. 185 



Hartt, but differs in its somewhat greater length and narrower sub- 

 angular ribs. It appears to be less transversely extended and the 

 cardinal angles less acutely pointed. As in other respects it appears 

 indistinguishable it may not perhaps constitute more than a variety. 

 It bears much resemblance in shape to Sj). medialis Hall," as well 

 as to Sp. mucronatus Conrad, ! and has the subangular sinus on the 

 pedicle valve limited by stronger plicatioiis as in the latter species. 



Specimens of this form occur in the Bain Collection on the blocks 

 of sandstone with Sp). orbignyi, from which they ai'e easily dis- 

 tinguished by the more numerous and narrower plications, the sub- 

 angular sinus with its stronger bordering ribs in the pedicle valve, 

 and the narrower more slowly expanding and more elevated fold in 

 the brachial valve. 



Dimensions. — Pedicle valve (No. 146), Length 25 mm. ; width 

 42 mm. 



Localities.— (No. 146) Gamka Poort. (No. 109) Ditto. 



SPIPJFEK (RETICULAEIA?) sp. /I 

 (Plate XXIII., fig. 4.) 



There is one large cast (No. 139) of a nearly perfect pedicle valve 

 which is characterised by its smooth non-plicated surface. The 

 valve is of a transversely semi-elliptical shape with rounded cardinal 

 angles ; the beak is prominent and tall ; the hinge-area is high and 

 nearly vertical ; a deep broad smooth rounded sinus with slightly 

 raised margins runs down the iniddle. The surface is devoid of ribs, 

 and smooth except for the strong impressions of the diductor and 

 adductor muscles and the so-called "ovarian" pittings on each side 

 of the beak. 



Dimensions. — Length 30 mm. ; width 45 mm. 



Affinities. — The shape, sinus, and height of the beak and hinge- 

 area recall Sp. orbignyi, but the absence of ribs easily distinguishes 

 it. The American form Sp. Icevis Hall,.'!: from the Portage Group, 

 agrees in the shape, smooth surface, and median sinus, but the beak 

 is not so prominent nor the hinge-area so high. 



Sp. nudus Dav.,? from the English Middle Devonian, has also a 

 general resemblance, and has as large a beak and hinge-area. 



Locality. — (No. 139) Uitkomst, Ceres. 



* Hall, Palaeont. N.Y., vol. iv., 18G7, p. 227, pi. xxxviii., figs. 1-25. 



t Ibid., p. 216, pi. xxxiv., figs. 1-23. 



\ Ibid., p. 239, pi. xxxix. 



§ Davidson, Mon. Brit. Foss. Brach., vol. iii. , p. 38, pi. iv., fig. 17. 



