from Southern Nigeria. 201 



(B) A Cretaceous PeJecy pod from Southern Nigeria. 

 (PI. VI. figs. 18, 19, 20.) 



Among- some small indeterminable fossils obtained by- 

 Mr. Parkinson from certain bore-holes in the Lagos province 

 of Southern Nigeria is a fragmentary Pelecypod valve which 

 is of considerable importance, as it implies the presence of 

 Cretaceous rocks in that area. The specimen referred to 

 belongs to the genus Veniella of Stoliczka, better known 

 among African Cretaceous fossils as tloudaireia of Alunier- 

 Chalmas, the synonymy of which has been recently reviewed 

 by the present writer* in an account of some Ci'etaceous 

 shells from Zululand. 



Veniella auressensis {?}, Munier-Chalmas, sp. 



Triyonia auressensis, C/oquand, G(5ol. Pal. Coiistautine, 1862, pi. xii. 



fiffs. ]0, ll,p. 203. 

 Houdairia drui, Miinier-Chalmas, Mission M. le Com. Roudaire Chotts 



Tunisiens, 1681, pis. iv., v. pp. 74-77. 

 Roudaireia auressensis, Perou, Desc. Invert. Foss. Cretac^s Tunisie, 



Explor. Scient. Tunisie, 1893, pi. xxix. figs. 10-12, p. 299. 

 Roudairia drui, Quaas, Fauna obersten Kreidebild. libyschen VViiste, 



Pftlaeontographica, 1902, vol. xxx. part 2, pi. xxiv. figs. 20-22, p. 221. 



The specimen is represented by a small umbonal fragment 

 of a left valve, showing the remains of a wide and robust 

 hinge-plate, but without the dentition being preserved, over 

 which curves a subacute umbo with its nucleus touching the 

 upper margin of the hinge-plate. 



The trigonal character of this genus is well expressed in 

 the specimen, which, moreover, exhibits the prominent 

 oblique carina dividing the anterior from the posterior regions. 



Thick horizontal lidges, curving upwards at their anterior 

 ends, ornament the shell in front, which are widely separated 

 during the progress of development, finer striations occurring 

 within at the earlier stages of growth, otiierwise the furrows 

 are smooth ; a well-defined lunul ite area is also present. 



The posterior side is abrupt and furnished with a nearly 

 median ridge, whilst the surface is closely and obliquely 

 ornamented with lines of microscopical size ; the ventral 

 margin is broken, so that the original height of the specimen 

 is unknown, although it probably represents an examj)le 

 which might have been 30 mm. 



Dimensions (umbonal fragment) .-*-Length = 7, hei('jit = 

 5 mm. 



* Trans. Royal Soc. South Africa, 1909, xo\ i. pp. 67-69. 



