578 MR R. BULLEN NEWTON ON SOME CRETACEOUS BRACHIOPODA 



Probably this is a form more or less intermediate in character between the Tertiary 

 and Cretaceous species mentioned, but further material is required for a more 

 accurate determination. 

 Dimensions. — 



Length ...... 30 mm. 



Diameter . . . 22 „ 



Occurrence. — Accompanying Cardium sp. and other shell remains, crinoidal 

 stem ossicles, etc., in a cream-coloured limestone. 

 Locality. — No. 286 — Plateau N. of Lobito. 



Fam. Akerid.e. 



Akera gregoryi, sp. nov. (PI. II, fig. 2.) 



Deselection. — Shell very large, broadly ovate, ventricose ; volutions three 

 (probably), slightly projecting above outer whorl, deeply canaliculated at suture ; 

 last whorl widely convolute, subcylindrical in front for half its length, columella 

 broadly excavated anteriorly ; aperture extensive, curved, narrowing posteriorly, 

 widest in front, outer lip free at the summit ; sculpture showing distant, longi- 

 tudinally curved growth lines without flexuosity. 

 Dimensions. — 



Length ...... 60 mm. 



Width (maximum) . . . . 50 ,, 



Remarks. — This description applies to a natural limestone cast which probably 

 represents one of the largest forms of Ahera yet referred to in literature. Not a 

 vestige remains of the delicate thin shell that once invested the surface, and which 

 is so characteristic of the genus. The specimen is related to Coquand's * Bulla 

 tevesthensis from the Turonian of Algeria, and to a lower Turonian form from Syria 

 described by Whitfield f as Akera siliciosa ; but affinities of possibly greater 

 alliance may be traced with C. A. White's j Akera broivni from the Cretaceous of 

 Brazil, a species showing considerable resemblance in general contour, but of smaller 

 dimensions, being only about half the size, besides possessing distinctly sinuous 

 growth lines, a lesser anterior excavation of the columella, and an outer lip terminat>- 

 ing with a closer attachment to the spire. Unfortunately, the Brazilian type is 

 without definite locality, the species being stated to occur both at Sergipe and 

 Pernambuco, the rocks of which areas, according to Kossmat, are of different 

 Cretaceous horizons, the Sergipe deposits belonging to the Schloenbachia injlata 

 group, whereas those of Pernambuco are of later age and would be recognised as 

 equivalent to the Ariyalur stage of India or the Danian of Europe. 



* (Hoi. Pal. H. Gonstantine, 1862, pi. v, fig. 9, p. 189. 

 t Bull. American Mus. Nat. Hist., 1891, vol. iii, pi. x, figs. 14, 15, p. 441. 



I "Contributions to the Paleontology of Brazil," Archiv Mus. Nation. Brazil, 1888, vol. vii, pi. ix, figs, (i-8, 

 p. 200. 



