Jones and Sherhorn — Tertiary JEntomosfraca. 391 



From the Weyboum Crag, East Runtou. Mr. C. Eeid. (Mus. 

 Pract. Geol.) 



23. Cythere akenosa, Bosquet. PI. XL Fig. 4. 



This is one of the papulated forms of Cythere, the surface having 

 low, tubercular, and obscure meshes, which in other instances form 

 strong tubei'cles. In some cases these become ragged warts (C. 

 scahra, Munster ; see Bosquet, Entom. Tert., p. 103, pi. v. fig. 7); 

 in others they pass into spines ( C. ericea, C. irjpex, and others ; G. 

 S. Brady. "Challenger Ostrac," pi. xvii. and xviii.) ; we have also 

 a passage-form. The above and two following forms have a subovate 

 edge-view. They were found in the London Clay of Piccadilly, 

 London, by Messrs. Sherhorn and Chapman. 



24. Cythere scabropapulosa, Jones. PI. XL Fig. 5. 



This specimen from the London Clay of Piccadilly is more 

 uniformly convex and more rounded posteriorly than the Brackle- 

 shani specimen figured in the Monograph, 1856, pi. v. fig. 16. 

 Moreover, the anterior margin is strongly denticulated, but the 

 dorsal edge is not quite so roughly tuberculate as seen in the valve 

 from Bracklesham. 



Dr. G. S. Brady's " C. scabropapulosa " from the Antwerp Crag 

 (Trans. Zool. Soc. vol. x. p. 393, pi. Ixvi. fig. 2), being much rougher 

 and more warty, is nearer to C. scahra, Munster, and might be 

 regarded as C. scabi-opapulosa, var. riidis. 



25. Cythere scabropapulosa, Jones, var. aculeata, nov. 



PL XL Fig. 6. 



This is a well-grown valve of C. scabropapulosa becoming hispid, 



by the tubercles ending with a sharp prickle or spine. A further 



development of this spinose condition is seen in C. irpex, Brady, as 



above mentioned. This also is from the London Clay of Piccadilly. 



26. Cythere gyriplicata, sp. nov. 



Narrow- suboval in outline, hinge-line slightly convex, but distinct. 

 Ends rounded ; narrow behind, somewhat oblique in front. Surface 

 sculptured with delicate longitudinal ridges, arranged concentrically 

 towards the margins, and united by smaller transverse ridges. 



From the Belosepia-hed of Bracklesham. T. R. Jones' Collection. 



The nearest species we know of is Bosquet's C. multicostata, Entom. 

 Tert., p. 59, pi. ii. fig. 12 ; but this is very much coarser and broader, 

 and without any sign of reticulation. 



27. Cythere delirata,^ sp. nov. 



A Cythere of the not uncommon sub-oblong form, but with the 

 rare ornament of slight furrows diverging up and down from the 

 median line of the posterior region, and becoming more or less 

 concentric or confused anteriorly. Edge view long-oval. 



From the Fluvio-marine beds of Headon Hill, Isle of Wight. 

 (Fred. Edwards' Collection in the British Museum.) 

 ^ Ploughed with diversent furrows. 



