386 Annals of the South African Museum. 



of Brazil, which Clarke ■'- has also described from Erere. Thomas t 

 more recently has compared with this species a specimen from 

 Argentina, Ours is too imperfect for a minute comparison, but the 

 general shape of the whorls and proportions of the shell agree well 

 with it. It is closely similar to the shell described by Whidborne \ 

 as Bellerophou {Tropidodiscus) trilohatus Sow., yqx . hisulcatus Eoem., 

 from the English Upper Devonian, and seems almost indistinguish- 

 able from the one figured by Beushausen § from the Spirifer Sand- 

 stone of the Upper Harz as Bellerophon bisulcatus Eoem. 



BELLEEOPHON (PLECTONOTUS) FEATEENUS sp. nov. 

 (PL XLVII., figs. 3, 3a, 4.) 



The almost perfect internal casts of two shells of a Belleroplion 

 lying in close contact on the same piece of rock from Whupperthal 

 enable us to define a new form which, while undoubtedly allied to 

 B. salteri, Clarke,!] appears to merit specific distinction, for the 

 shell expands more rapidly towards the mouth, the whorls are less 

 deep, the umbilicus is larger, and the mouth is more transversely 

 elliptical. 



Description. — Shell large, broad-backed, subglobose, faintly trilobed, 

 rapidly expanding to a wide transversely elliptical mouth. Umbilicus 

 large, deep, open, with subangular margins, in diameter nearly one- 

 third the height of the shell. "Whorls broad, low, increasing in height 

 rather rapidly, about half as high as broad, with rather sharply 

 rounded lateral edges ; faintly trilobed by two weak spiral furrows, 

 each lying about half-way between the middle line and lateral edges 

 of whorls, leaving a low, indistinct dorsal lobe between them which 

 does not rise above the general convexity of the dorsum and 

 occupies about the middle three-fifths of its width. Mouth suddenly 

 expanded laterally with reflexed lower lip, and with dorsal margin 

 excavated by deep but not wide V-shaped notch, forming large 

 rounded lobes to the aperture. 



* Clarke, Palseoz. Faunas of Parii, Brazil, 1899 (Archiv. Mus. Nac. Eio de 

 Janeiro, vol. x., 1899), p. 40, t. iii., figs. 10, 11. 



t Thomas, Zeitschr. deut. geol. Gesell., Bd. Ivii., 1905, p. 253, pi. xii., 

 figs. 13a, h. 



\ Whidborne, Mon. Brit. Dev. Fauna (PalaBont. Soc), vol. iii., pt. i., 1896, p. 68. 



§ Beushausen, Beitr. Kennt. Oberharz. Spirifersandst. (Abhandl. geol. specialk. 

 Preuss., vi.. No. 1, 1884) p. 45, t. ii., figs. 3a, h. 



II Clarke, op. cit., p. 39, pi. iii., figs. 12, 13. 



