9 2 R. BULLEN NEWTON on 



to the ovatiform marginal curvature, ventral margin elongately curved ; teeth 

 consisting of two divergent cardinals each provided with a groove at the 

 summit, the anterior tooth thickening with age and becoming coalescent with 

 the strong cardinal fulcrum, lateral teeth obsolete ; the adductor scars are 

 unequal, the anterior being elongate while the other is much rounder, both 

 are concentrically and radially striated ; an obscure and, more or less swollen 

 rib proceeds obliquely along each side of the floor of the valve from beneath 

 the cardinal arch to the inner margins of both the adductor scars ; pallial 

 line with an extensive elliptical indentation extending nearly horizontally 

 beyond the middle of the valve and more or less parallel with the ventral 

 margin, sometimes the upper line of the sinus or indentation gradually and 

 obliquely ascends to the margin of the posterior adductor scar ; sculpture 

 exhibits fine concentric lineations grouped into regular periods of growth, 

 crossed by innumerable delicate radial striations, whilst the posterior angula- 

 tion is furnished with two or three nearly obsolete radial ribs ; close vertical 

 striations cover the wide, internal marginal surface of the ventral region. 



DIMENSIONS. 



Adult. 



Height 52 millimetres. 



Length ... 70 



Diameter (united valves) 30 



REMARKS. This large Tellinoid shell is well represented in the collection ; 

 the valves being generally in an isolated condition although some of them 

 are capable of being accurately paired. The specimens agree with the 

 contour lines of Tellina pellucida, T. zitteli, T. grandis, and T. latissima, 

 from the Egyptian Eocenes, as delineated by figures and descriptions 

 published by Mayer-Eymar, 1 and continued by Oppenheim, 2 the latter 

 regarding such species as one form of shell under the specific name of 

 zitteli. In other important respects, however, the Nigerian valves differ 

 from the Egyptian shell. They are of much deeper construction measuring 

 more than double the diameter of the Egyptian valves, an adult form of 

 which, as quoted by Oppenheim, yielding a height and length respectively of 

 56 and 75 millimetres shows a diameter of only 13 millimetres for their united 



1 Palaeontographica, 1883, Vol. 30, pi. 23, figs. 14, 15, p. 71 ; and Journ. Conchyl., 1898, Vol. 46, 

 pi. 3, fig. 6, pi. 13, figs, i, 3, pp. 28, 230, 231. 



Palaeontographica, 1906, Vol. 30, part 3, pi. 18, fig. 19, pi. 19, fig. 12, Text-figs. 14, pp. 179, 180. 



