206 Mr. D. Sharpe on PalcBozoic Fossils from South Africa. 



Encrinital joints and stems. PI. XXV. figs. 21-28 



Ophiocrinus Stangeri, Salter. PI. XXV. fig. 20 ? 



Warm Bokkeveld, Cold 

 Bokkeveld, Cedarberg, 

 Gydow Pass, and Kok- 

 mans Kloof. 



Description of Palaozoic Mollusca from South Africa. 

 By Daniel Sharpe, Esq., F.R.S., Pres.G.S. 



Spirifer Antarcticus, Morris and Sharpe, Quart. Journ. Geol. Soc. vol. ii. pi. xi. 

 fig. 2. PI. XXVI. figs. 1,2, & 5. 



S. testa crassa semicirculari, costis 20-24 rotundatis elevatis concentrice subimbricatis : 

 costa media ventrali magna, elevata, imbricata : sulco medio dorsali lato, profundo, rotundato : 

 are& cardinali latitudine valvarum ; dorsali elevata, triangulari, longitudinaliter lineat& ; ventrali 

 elevata, rectfi. 



Shell transversely semicircular, with twenty to twenty-four prominent, rounded 

 ribs, slightly imbricated by the concentric lines of growth : mesial ridges of the 

 ventral valve large, elevated, and imbricated ; mesial furrow of the dorsal valve 

 large, deep, and rounded. Hinge-area of the breadth of the shell ; on the dorsal 

 valve high and triangular, with strongly marked longitudinal lines ; on the ventral 

 valve high and bounded by parallel lines. 



Breadth 2^ inches ; length of dorsal valve \^ inch, of ventral valve 1^ inch ; 

 height of hinge-area on the dorsal valve ^ inch, on the ventral valve ^ inch. 



Found in the Warm Bokkeveld ; occurring abundantly as casts in a hard grey 

 siliceous rock, together with casts of Sp. Orhignii, Terebratula Bainii, Orthis 

 palmata, and Chonetes, chiefly on the bedding-planes of the rock ; also in a light- 

 coloured soft sandstone of the same locality. 



It has been also found in the Falkland Islands by Mr. C. Darwin. 



The better preservation of the African specimens enables me to improve the 

 description originally given of this species ; but it is still far from complete : its 

 most marked feature is the height of the hinge-area on both valves. 



Fig. 1, cast of the interior of the dorsal valve; fig. 2, cast of the interior of 

 the ventral valve, with the exterior of the dorsal area ; fig. 3, exterior of the dorsal 

 valve, from a gutta-percha mould of an impression of the shell. 



Von Buch has described a species of Spirifer brought by Dr. Krauss from Kok- 



