Brachiopoda from the Bokkcveld Beds. 181 



of the original specimens of -S^;. antarcticus and Sp. orbiijivji from 

 Cape Colonj^ described and figured by Sharpe * in 1856, I am con- 

 vinced that they all l)elong to one species (with perhaps the exception 

 of the one figm-ed op. cit., pi. xxvi., fig. 6), the apparent differences, 

 such as the height of the hinge-area, being not constant and in 

 most cases due to the state of preservation. The number of ribs 

 in those specimens figured by Sharpe as Sp. antarcticus is only 16, 

 and those near the cardinal angles are very faint ; but in Morris 

 and Sharpe's f desci'iption of the type from the Falkland Islands, 

 the number is stated to be 20-24 ; in none of the South African 

 specimens which resemble this species in most other respects 

 does the number exceed 18, and it is generally 16 and sometimes 

 only 12. The specimens from Cape Colony figured by Sharpe as 

 Sj). orhignyi resemble in all respects those ascribed by him to 

 Sp. antarcticus from the same region; one {op. cit., pi. xxvi., fig. 3) 

 has 18-20 ribs on the pedicle valve, but the last three on each side 

 are faint. Morris and Sharpe {op. cit.) stated that Sp. orhignyi 

 possessed about 20 rounded imbricated ribs. The height of the 

 hinge-area and all other features are identical with those specimens 

 referred by Sharpe to Sp. antarcticus from Cape Colony. 



It seems therefore advisable to refer all these South African forms 

 to the same species, and as in number and character of the ribs and 

 sinus they agree best with Sp. orhignyi as originally described by 

 •Morris and Sharpe, they may safely be ascribed to this species, the 

 typical Falkland Sp. antarcticus having too many ribs, and the ribs 

 also being sharp instead of rounded, and the sinus on the pedicle 

 valve angulated. The opinion, however, that the original Sp. 

 orhignyi of the Falkland Islands may prove to be only a variety of 

 the original Sp. antarcticus from the same locality cannot be com- 

 pletely abandoned ; and if this turns out to be the case the latter 

 name has the priority. The species from South Africa called by Von 

 Buch Sp. capensis,\ or that from South America called by D'Orbigny 

 Sp. holiviensis,% may be identical with Sharpe's species, but we know 

 too little about them for certainty, and the figures of the types are 

 poor. Kayser |j holds the view that Sp. antarcticus and Sj). orhignyi 



* Sharpe, Trans. Geol. Soc, ser. 2, vol. vii., pi. xxvi., figs. 1, 2, 5, p. 206 {Sp. 

 autarcticua); and pi. xxvi., figs. 3, 4, 6, p. 207 (Sp. Orhignyi). 



t Morris and Sharpe, Quart. Journ. Geol. Soc, vol. ii., 184(3, p. 276, pi. xi., fig. 2. 



+ Von Buch, Biiren-Insel, p. 12, fig. 1. 



S D'Orbigny, Voyage dans I'Amerique Meridionalc (1842), vol. iii., Palteont., 

 p. 37, pi. ii., figs. 'J. 



jl Kayser, Zeitschr. dcut. Geol. Gesell., xlix., 18'J7, p. 207, t. ix., fiys. 1-4. 

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