28 CRETACEOUS ENTOMOSTRACA. 



9. Ctthereis vallata, Jones. Plate II, fig. 19. 



Ctthere (Cttheeeis) vallata, Jones, MS. Syst. Lists, &c., Belfast Nat. Field 



Club, vol. i. Appendix iii, 1875, 

 p. 81. 



Length '85; height "37 mm. 



Long, subtriangular, rounded in front, with flat margin (broken) ; tapering 

 backwards, and suddenly contracted to a point at the depressed posterior margin. 

 A raised ridge within the front margin curves backwards ventrally, and, before it 

 ends bluntly at the postero-ventral angle, it gives off, or is replaced by, a thicker 

 oblique ridge, which joins a short dorsal ridge, so that the body of the valve is 

 surrounded by a nearly continuous wall-like ridge or vallum, of an ovate outline. 



Locality. — Ghalh, Island Magee, opposite Magheramorne, co. Antrim. (Unfor- 

 tunately broken since it was figured.) 



10. Cythereis spinioaudata, sp. nov. Plate II, figs. 17, 18. 



Length '7 ; height '32 ; thickness "2 mm. 



A very neat, subtriangular, depressed form, rounded in front ; nearly straight 

 (but sloping) on the upper and lower margins, each of which ends with an acute 

 angle, and has the depressed and sharply cuspidate posterior margin between 

 them. A subcentral knob, smooth ventral ridge, and neat, but rather coarse, 

 punctate ornament help to characterize this species. 



Several individuals without the long caudal spine have been obtained from the 

 washings of the Chalk-rock of Dunstable, with which Mr. A. J. Jukes-Browne, 

 F.G.S., has favoured us. The long delicate spine has probably been broken off by 

 trituration among the rough particles of the material washed. 



It is not far removed from G. vallata^ PI. II, fig. 19 ; and may also be compared 

 with C. Geinitzi, Reuss, * Elbthal.,' p. 146, pi. xxvii, fig. 4, as having some features 

 in common ; also G. insignis, Reuss, ' Zeitsch. d. g. Ges./ 1855, p. 281, pi. x, 

 fig. 9; and Marsson's G. acutiloba, 'Mittheil., &c.,' 1880, p. 42, pi. iii, figs. 11 a, h. 

 Localities. — Ghalh, Horstead, and Keady Hill, co. Londonderry; Ghalk-rock, 

 Dunstable. 



