20 CRETACEOUS ENTOMOSTRACA. 



Specimens of this particular form have been obtained by Mr. F, Chapman 

 from the Gault of Folkestone (Kent) and Godstone (Surrey). Figs. 53 and 54 

 are typically suboblong, broadly rimmed and denticulate in front, and bear the 

 two longitudinal swellings characteristic of this species. The dorsal edge is 

 tuberculate at and behind the anterior hinge ; the hinder margin is contracted, 

 depressed, and strongly toothed. 



Fig, 55 is shorter and more ovate; the dorsal edge is more arched, and 

 thickened into a third low ridge, and the front marginal rim is thick, smooth, 

 obliquely curved, and set on (as if by accident) far back, close against the 

 anterior ends of the three ridges. In some respects this valve loses the chief 

 characteristics of figs. 53 and 54 ; but neither its three ridges nor the front and 

 hind margins match the features of G. triplicata^ (figs. 56 and 57). A somewhat 

 similar abnormal individual is in Mr. Chapman's collection from Folkestone. 



Localities. — Chalk-rocJc, Dunstable; Gault, Godstone and Folkestone; Neocomian, 

 Haute-Marne, France. 



3. Cttheeeis quadrilatbra {Bomer). Plate I, figs. 69 — 75. 



CxTHEEiNA QTTADBiLATEEA, Bomer. Verstein. norddeutsch. Kreidegeb., p. 105, 



pi. xvi, fig. 19. 

 Cytheee haepa, Gornuel. Mem. Soc. geol. France, ser. 2, vol. i, pt. 1, I8I16, 



p. 199, pi. viii, fig. 13. 



— ATTEiCTJLATA, var. SIMPLEX," Comuel. Mem. Soc. geol. France, ser. 2, vol. 



iii, pt. 1, 1848, p. 243, pi. iii, 

 figs. 10, 11. 

 Cttheeeis quadeilateea, Jones. Monogr. Entom. Cret., 1849, p. 18, pi. iii, figs. 



10 a—f; pi. iv, figs. 10 y— /. 

 Cytheee filicosta ? Marsson. Mittheil. nat. Ver. Neu-Pommern und Eiigen, 



Jahrg. 12, 1880, p. 43, pi. iii, figs. 12 a, h. 



— (Cttheeeis) quadeilateea, Jones. Quart. Journ. Geol. Soc, vol. xl, 



1884, pp. 766, 772, pi. xxxiv, figs. 

 39—41. 



Fig. 69, large valve. Length 1*16 ; height •61 ram. 



Fig. 70, small valve. ,, 1-16; „ '5 ,, 



Fig. 71, adult. ,, 1-05 ; thickness '55 mm. 



Fig. 72, adult. Height -61 ; thickness "55 mm. 



Fig. 73, medium growth. Length 1*03 ; height '52 mm. 



Fig. 74, young individual. „ '61 ; „ "305 ; thickness '27 mm. 



^ Figs. 53, 54, and 55 are magnified 25 diam., whilst figs. 56 — 61 are magnified only 18 diam. 

 2 " C. harpa " is given up in favour of this variety by M. Cornuel at p. 243. 



