Neiv Fossils from the Bokkevcld Beds. 403 



KENSSEL^KIA aff. STEWAETI Clarke ? 



The difficulties which surround the correct determination of the 

 ribbed shells with the external aspect of Bensselceria are usually 

 increased in dealing with the Bokkeveld fossils by their poor state 

 of preservation. Imperfect internal casts or external impressions 

 of one such type of an oval shape, measuring about 14 mm. long by 

 11 mm. wide, and with 30-40 low rounded equal ribs, have much 

 the appearance of Clarke's B. steivarti * from the Lower Devonian 

 of Dalhousie, N.B. But no satisfactory determination is possible. 

 It has more numerous and finer ribs than my B. sp. /3,| which 

 Schwarz \ wishes had a specific name, but the trouble caused by 

 giving new names to insufficiently defined species is too well known, 

 though sometimes it may be unavoidable. 



Loccdities. — Gydo Pass ; Ladismith. 



Genus SCAPHIOCCELIA Whitfield, 1891. 



SCAPHIOCCELIA ? AFEICANA Eeed. 



(PI. XLVIIL, fig. 9.) 



A full description of this interesting brachiopod was given by me 

 on a previous occasion, § and the two fine examples from Montagu 

 now before me furnish few additional particulars. Thej^ are in the 

 condition of internal casts like the types. The dental plates are 

 found to thicken into short blunt processes (teeth) at their free 

 anterior ends which curve inwards slightly on each side of the 

 cardinal callosity of the opposite valve. This feature was not well 

 seen in the other specimens. One of the present specimens is 

 transversely extended owing to compression, and has the hinge-plate 

 medianly divided by a groove instead of merely centrally pitted. The 

 other seems to have kept its natural shape and shows the typical 

 characters. The carination of the pedicle valve and the deep sul- 

 cation of the opposite valve are strongly expressed, just as Whitfield 

 described in the type of the genus from Bolivia. 



The undistorted one measures 65 mm. long, 40 ram. wide, and 

 only 20 mm. thick in the middle of the sulcus. 



* Clarke, Bull. N.Y. State Mus., No. 107, 1907, pp. 28;), 240. 



t Keed, Ann. S. Afr. Mus., vol. iv., pt. 3, p. 177, pi. xxi., lig. 9. 



I Schwarz, o^. cit., p. 365. 



§ Eeed, Geol. Mag., Dec. 5, vol. ill., 1906, p. 306, pi. xvii., figs. 1-3. 



