38 



CRETACEOUS ENTOMOSTRACA. 



anterior part of the surface has a low narrow ridge curving from below to the 

 antero -dorsal angle ; the body of the valve has a broad swelling with a backward 

 and downward (ventral) curve, ending in a long, sharp, tapering spine, pointing 

 downwards and outwards. The hinder part of the valve is depressed, sloping and 

 narrowing to the end. The dorsal edge, besides the tubercle at its front angle, 

 already noticed, has a similar projection at or below the place of the anterior hinge, 

 and a small tubercle behind it. There are also some irregular prickles on the upper 

 and lower margins. 



Localities. — Chalk, Horstead, Norfolk, and Keady Hill, co. Londonderry. 



6*. Cytheropteron cuspidatqm, sp. no v., var. montiiosa, nov. (vel cuspidatmn- 



montuosum). Plate III, figs. 14 — 16. 



CxTHEEE (Cytheeeis) montxjosa, Jones, MS. Syst. Lists, &e., Belfast Nat. Field 



Club, vol. i, Appendix iii, 1875, 

 pp. 81, 92. 



Length '75 ; height '3 ; thickness (with spines) '5 mm. 



In this variety the curved swelling on the ventral region is not interrupted in 

 front, and it bears two subcylindrical tubercles, or short blunt spines, the hinder 

 of which is longer than the other. There are three isolated pointed tubercles on 

 the dorsal edge, towards two of which the ends of the ventral swelling curve 

 upwards. 



Localities. —Chalk, Island Magee, co. Antrim; Greensand, Warminster. 



6**. Cytheropteron cuspidatum, sp. nov., var. tricuspidata, nov. (vel cuspidatum- 



tricuspidatum). Plate III, figs. 6, 7. 



Length '65 ; height "25 ; thickness (with spines) '6 mm. 



Here the ventral swelling of the valve's surface is developed into three strong, 

 conical, unequal, and more or less divergent spines. 

 Locality. — Chalk, Horstead, Norfolk. 



7. Cytheropteron pedatum {Marsson). Plate IV, figs. 33 — 35. 



CrTHEttE PEDATA, MarssoH. Mittbeil. naturw. Ver. Neu-Vorpommern und Uiigen, 



Jahrg. \\\, 1880, p. 46, pi. iii, figs. 16 a— c. 



