32 CRETACEOUS ENTOMOSTRACA. 



with age, as shown in the series of figs. 2/, /', g^ h, and i, in PI. I of the former 

 Monograph, 1849. When the surface is occupied by neat concentric wrinkles, 

 somewhat more perfect even than shown in M. Bosquet's fig. 2, ' Mem. Liege,' 

 vol. iv, pi. ii, these little valves are charmingly pretty (see Cornuel's figure, loc. cit., 

 and PI. IV, fig. 19). Considerable resemblance in contour and in style of orna- 

 ment is to be seen between some individuals of G. concentricum and some recent 

 forms, such as C. depressum^ B. and N., ' Trans. R. Dublin Soc.,' 2nd ser., vol. iv, 

 1889, p. 219, pi. xxi, figs. 1, 2; also G. latissinmm (Norman), ' Monogr. Post-Tert. 

 Bntom.,' p. 202, pi. viii, fig. 23 ; and particularly between G. Mofitrosiense, B. C. 

 and R., as figured in the ' Ann. Mag. N. H.,' ser. 4, vol. ii, pi. v, figs. 4 and 5 

 (young), and ' Trans. R. Dublin Soc.,' 1889, p. 216, pi. xix, figs. 26 and 27 (adult), 

 and Bosquet's figure above quoted. Some Gytherse, such as G. Speyeri, Brady, as 

 given in the ' Trans. R. Dubl. Soc.,' 1889, p. 141, pi. xvii, figs. 16, 17, have to some 

 extent this kind of carapace ; and Reuss's C. texturata, ' Zeitsch. d. g. G.,' vol. ii, 

 p. 286, pi. X, figs, a — d, comes very near to this form. 



Some figures selected from the former series are here reproduced on a smaller 

 scale. Fig. 5 (the former fig. 2j) is an old very much worn valve, from the 

 Greensand of Warminster. Fig. 6 (reduction of 2/) is a left valve, young, 

 with the sculpturing of pits and spinous meshes unworn ; and fig. 7 (fig. 2 h) 

 is a left old, though smaller, valve, with the ornament changed to interrupted 

 corrugation or wrinkles (like " dot and dash " in telegraphy), rounded, smooth, 

 and more or less concentric. Some individuals show the lines of punctations 

 without the intermediate mesh-walls being prickly. 



Localities. — Chalk, Horstead and S.B. England, Magheramorne (Antrim), and 

 Keady Hill (Londonderry) ; Ghalh-roclc, Dunstable ; Ghalk-marl, Didcot and 

 Dover ; Detritus, Charing ; Gault, Folkestone and Leacon Hill ; Greensand, 

 Cambridge and Warminster. Very similar in the T]])per Oolite, Ridgway, Dorset. 



Foreign. — Chalk, Maastricht, Riigen, Bohemia, &c. ; Neocomian, Haute-Marne, 

 France. 



1*. Cttheropteron concentricum (Beuss), varietas virginea, Jones (vel concentricum- 



virgineum). Plate I, figs. 14 — 17. 



Cttheee PUNCTATUIA (non Burner), var. vieginea, Jones. Monogr. Entom. Cret., 



1849, p. 12, pi. i, fig. 2 n. 



Cypeidina (Cttheeina on the plate) Althi, Reuss. Haid. Nat. Abhandl., vol. iv, 



pt. 1, 1850, p. 49, pi. vi, figs. 10 a—c. 



Cytheee punctatula et var. vieginea, Bosquet. Mem. Cour., <fec., Acad. Belg., 



vol. xxiv, 1852, pp. 73 and 74, 

 pi. iii, figa. 10 a — d. 



