Notes on Fossils from the Falkland Islands. 253 



fold is 9 mm. There are eight rounded rihs on each side of 

 the fold, the outer ones being rather smaller than the inner 

 ones. These ribs are wider than the grooves between them. 

 The whole surface of the valve is marked by distinct thread- 

 like lines of growth, which, at irregular intervals, are more 

 strongly developed. The extremities of the hinge-line are 

 not so clearly seen in this specimen as in some others ; but 

 it is evident that they were never so sharp in the dorsal as 

 in the ventral valve. 



Having examined the type specimens now in the British 

 Museum, which were figured and described by Morris and 

 Sharpe, I have no hesitation in referring the specimens above 

 described to their Spirifera antarctica. It is true that in 

 their description this species is said to have twenty to 

 twenty-four ribs ; but the specimens do not bear this out. 

 The example with the most numerous ribs is the one figured 

 on their plate xi. fig. 2a, and on this I can only count nine 

 ribs on one side of the median ridge, and then towards the 

 angle of the shell there is a space devoid of ribs, as in Mr 

 Bruce's specimens. 



I am strongly of opinion that the specimens called Spiri- 

 fera Orhignii by Morris and Sharpe are only yoimger examples 

 of S. antarctica. Mr R. Etheridge, jun., could only certainly 

 recognise the one species of Spirifera, S. antarctica, among 

 the fossils which the " Challenger " brought from the Falk- 

 land Islands. 



Daniel Sharpe, in his description of the South African 

 fossils in 1856, retained the two species Spirifera antarctica 

 and S. Orhignii ; but Mr F. E. C. Reed, in 1893,i thought 

 that the South African forms should all be referred to 

 ^S'. Orhignii, and that the true S. antarcticits of the Falkland 

 Islands was not present among the South African specimens. 

 Mr Reed says : " After a careful examination of the original 

 specimens of S. antarcticus and S. Orhignii from Cape Colony 

 described and figured by Sharpe in 1856, I am convinced 

 that they all belong to one species (with perhaps the excep- 

 tion of the one figured, op. cit., pi. xxvi. fig. 6)." Mr Reed 

 shows further that, except for the greater number of ribs 



^ Annals of the South African Museum, vol. iv. p. 165. 



