388 Jones and Sherhorn — Tertiary Entomostraca. 



From the London Clay, Piccadilly ; collected by Messrs. Sherborn 

 and Chapman.^ 



10. Bairdia rhomboidea, sp. nov. 



A stiff-looking Bairdia ; broadly angular in front ; nearly parallel 

 above and below ; narrow behind, with a curve on the ventral, and 

 a slope on the dorsal edge of this end. The antero-ventral margin 

 is suddenly constricted, leaving a projection behind the antero-ventral 

 slope. The surface is very delicately punctate. 



From the White {Coralline) Crag of Sutton, Suffolk. 



11. Bairdia ovoidea, sp. nov. PI. XI. Fig. 3. 



A very small roundish Bairdia, pitted, resetted at the muscle-spot, 

 of a rather unusual pattern. It is like fig. 2, pi. iv., Monog. Tert. 

 Entom., but much less of a subdeltoidal shape, being well rounded 

 before, and slopingly curved behind, with the greatest fullness in the 

 front moiety ; hence, though both ends are somewhat obliquely 

 rounded, the anterior half of the valve is broader than the hinder 

 portion. 



From the London Clay, Piccadilly. Collected by Sherborn and 

 Chapman. 



Cythere, Miiller, 1875. 



Valves unequal (left valve usually somewhat larger than the 

 other), oblong-ovate to quadrate in shape, smooth or rough, mostly 

 highest in front ; hinge with teeth and sockets at anterior and pos- 

 terior angles, variously developed. 



The quadrate and rough forms have been classed as CytJiereis 

 {' Monogr. Cretac. Entom.,' 1849, p. 14) ; and, although this group 

 will not hold its own as a true genus, Dr. G. S. Brady having shown 

 that the animals do not differ from other Cytherce, yet it is a very 

 convenient grouping for paleeontologists, who have to study the 

 valves only of these small fossil Crustacea. 



12. Cythere recurata,'^ sp. nov. 



Oblong-reniform, nearly equal at the ends in the outline, but 

 thickest posteriorly, as seen in edge view. Approximating to fig. 7g, 

 of G. S. Brady's C. demissa, in pi. xii. of the "Eeport Challenger 

 Ostracoda," but more even in outline. Coarsely punctate ; the pits 

 somewhat in lines, but with a tendency to assume a concentric 

 arrangement on the front half of the valve. Others are of the same 

 outline, but differ in the ornament. 



From the " Norwich Crag " of Southwold. 



13. Cythere venxjstula, sp. nov. 



Oblong, rounded at the ends, broadly oblique in front, semi-circular 

 behind ; straight on the ventral margin, oblique dorsally by the 



^ In the ' Journ. E. Micros. Soc' ser. 2, vol. vi. p. 740, this specimen was 

 douhtfuUy collated with Sowerby's Cppris barbata (' Trans. Geol. Soc.,' ser. 2, voL 

 V. 1834, p. 131, pi. ix. fig. 1), but this was probably a Cythere. 



2 «' Finished in a workman-like manner." 



