Brachiopoda from the Bokkeveld Beds. 169 



Oeder protremata. 



Family STKOPHOMENID^. 



STEOPHEODONTA cf. CONCINNA (Morris and Sharpe). 



(Plate XX., fig. 6.) 



There is one specimen (No. 131) of the pedicle valve of a small 

 species of Stropheodonta from Warm Bokkeveld, Ceres, which is of a 

 transversely semi-elliptical shape, about one and a half times as wide 

 as long, with the hinge-line equal to the greatest width of the shell 

 and the cardinal angles slightly pointed. The convexity of the shell 

 is very slight, and the cardinal angles are flattened. The surface is 

 covered with fine radiating striae (only well seen in this cast near 

 the margins) numbering about 120 round the edges; the beak is 

 small and rises a little above the hinge-line, the teeth are stout 

 but small; there is a small median septum extending from the 

 beak for about one-third the length of the valve ; there are weak 

 dental lamellaB diverging at right angles and bordering the flabellate 

 diductor impressions. The hinge-area is narrow and linear. No 

 marginal spines are visible. 



Dimensions. — Length 13 mm. ; width 18 mm. 



Affinities. — In shape, ornamentation, and internal characters this 

 shell resembles Orthis concinna Morris and Sharpe * from the Falk- 

 land Islands. It is less transverse than Chonetes falklandicus Morris 

 and Shax'pe, which has also a different ornamentation. The American 

 form Stropheodonta perplana Conrad,! from the Upper Helderberg- 

 Chemung Groups of North America and the Devonian of Brazil 

 seems to be very similar in internal and external characters. 



Locality. — (No. 131) Warm Bokkeveld, Ceres. 



STEOPHONELLA sp. 

 (Plate XX., fig. 7.) 



There is an imperfect internal cast of a brachial valve (No. 128) 

 from Gydo Pass, Ceres, with the hinge-area of the pedicle valve 

 attached, which appears to be referable to the genus StropJwnella. 



* Morris and Sharpe, Quart. Jourii. Geol. Soc, vol. ii. , 184G, p. 275, pi. x., 

 fig. 2a, h. 



t Conrad, Journ. Acad. Nat. Soc. Philadelphia, viii., 1842, p. 257, pi. xiv., fig. 11. 



\ Clarke, Palseoz. Faunas of Para, Brazil (Archiv. Mus. Nac. Rio de Janeiro, 

 vol. X., 1899), English edit., 1900, p. 87. 



