342 Mr. F. Chapman on Ostracoda 



Cytheroi^teron concentricum (Reuss), var. virginea, Jones. 



Cythere j^imctatida (uon Eouier), var, virginea, Jones, 1849, Mon. 



Entom. Cret. p. 12, pi. i. fig-. 2 n. 

 Cytheropteron concentricum, var. virginea, Jones and Hinde, 1890, 



Suppl. Mon. Cret, Entom, pp. 32, 83, pi. i. figs. 14-17. 



This is a feebly marked, or even smootli, variety of the 

 preceding species. One of the carapaces from SwafFham is 

 translucent and most delicately marked with a minute puncta- 

 tion ; other specimens from the same locality show a slight 

 wrinkling on an otherwise smooth surface. C. concentricum^ 

 var. virginea^ has already been recorded from the Cambridge 

 Greensand, and it occurs with some frequency at Swaffhani. 



Its geological range extends from the Lower Greensand to 

 the Upper Chalk. 



Cytheropteron sphenoides (Reuss). 



Cythere sphenoides, Reuss, 1854, Denkschr. Akad. "Wiss. Wieu, raath.- 



nat. Class, vol. vii. p. 141, pi. xxvi. fig. 2. 

 Cytheropteron sphenoides. Jones and Iliude, 1890, Suppl. Mon, Cret. 



Entom. pp. 33, 34. pl.'i. figs. 18-20. 



One specimen only of this Cytheropteroyi was found in the 

 Cambridge Greensand of SwafFham. It had previously been 

 recorded from the Chalk-rock in this country. 



Cytheropteron cuspt'datiim, Jones and Hinde, var. montuosa 



(Jones). 



Cythere (Cythereis) monttiosa, Jones, MS., 1875, Syst. Lists &c., Belfast 



Nat. Field Club, vol. i., Appeudix iii. pp. 81, 92. 

 Cytherojjtcrun cu^pidutum, var. montuosa, Jones and Hinde, 1890, 



Suppl. Mou. Cret. Entom. p. 38, pi. iii. tigs. 14-16. 



One valve, agreeing very closely with the above authors' 

 figured specimen in the arrangement of the prominences on 

 the carapace, was found in the Cambridge Greensand at 

 SwafTham. The previously recorded specimens were from 

 the Greensand of Warminster and the Antrim Chalk. 



Cytheropteron umhonatuni (Williamson), var. acanthoptera 

 (Marsson). 



Cythere acanthoptera, Marsson, 1880, Mittheil. naturw. Ver. Xen-Vor- 



pommeru and Riigen, p. 4o, pi. iii. figs. 14 a-c. 

 Cytheropteron umhonatum (Will.), var. acanthoptera (Marssou), Jones 



and Hinde, 1800, Suppl. Mon, Cret, Entom. p. 41, pi. i. figs. 11-13, 



pi. iv. figs. 22-2y. 



This variety has not hitherto been found below the Chalk- 

 rock. The Carabridge-Greensand specimens show a marked 



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