Mr. A. S. Woodward on Atherstonia. 239 



margin within the test and a definite and clear line of suture 

 separates them from the interradial edges. The pairs of 

 pores are remote from the interradio-ambulacral suture and 

 there is not a vestige of a " process." 



The interradial swelling sometimes rises to a blunt, raised 

 edge separated by a little space from the peristomial margin. 

 This blunt part is doubtless a degenerated " ridge," and it 

 does not appear capable of affording origin or insertion to 

 muscular structure. 



It appears that Echinoconus is much lower in the scale of 

 Echinoidea with regard to perignathic structure than the 

 species of Discoidea^ and certainly these are degraded below 

 those of IlolectypuSj which have a feeble yet fairly perfect 

 girdle, jaws, and teeth. 



XXVIII. — On Atherstonia, a neioOenus of PaJxeoniscid Fishes 

 from the Karoo Formation of South Africa; and on a Tooth 

 of Ceratodus from the Stormberg Beds of the Orange Free 

 State. By A. Smith Woodward, F.G.S., F.Z.tS.;, of the 

 British Museum (Natural History). 



[Plate XIV.] 



The only remains of Palffioniscid fishes from the Early Meso- 

 zoic Karoo Series of South Africa hitherto described or figured 

 are some detached scales made known by Egerton * under 

 the names of Palaoniscus Bainii and P. sculptas. However, 

 through the generosity of the Hon. W. Guybon Atherstone, 

 M.D., F.G.S., of Grahamstown, the British Museum is 

 now in possession of a nearly complete fish from the Beaufort 

 Beds of Colesberg ; and it is the object of the present notice 

 to describe and discuss the principal characters of this fossil, 

 illustrated in the accompanying Plate XIV. figs. 1-3. 



Description. 



The specimen is shown, nearly one half nat. size, in PI. XIV. 

 fig. 1, and a flank-scale of the natural size in fig. 2, while a 

 few scales at the base of the dorsal fin form the subject of 

 fig. 3. I'he general form of the fish is well indicated ; but 

 the head is much crushed and its precise contour probably 

 destroyed, while the extremity of the caudal fin has been 



* Sir P. Egerton, " Note on the Fisli-remaius from Styl Krantz, South 

 Africa," Trans. Geol. Soc. [2] vol. vii. (1856), pp. 226, 227, pi. xxviii. 

 figs. 26-42. 



