342 Mr. F. Chapman on Ostracoda 



Cytheropteron concentricum (Reuss), var. virginea, Jones. 



Cythere punctatida (non Rbmer), var. virginea, Jones, 1849, Mon. 



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

 Cytkeropteron concentricum, var. virr/inea, Jones and Ilinde, 1890, 

 * Suppl. Mon. Cret. Entom. pp. 32, 33, pi. i. figs. 14-17. 



This is a feebly marked, or even smooth, 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. coneentricum, 

 var. virginea, has already been recorded from the Cambridge 

 Greensand, and it occurs with some frequency at Swaffham. 



Its geological range extends from the Lower Greensand to 

 the Upper Chalk. 



Cytkeropteron sphenoides (Reuss). 



Cythere sphenoides, Reuss, 18o4, Denkschr. Akad. Wiss. Wien, ruath.- 



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

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



Entom. pp. 33, 34, pi. i. figs. 18-20. 



One specimen only of this Cytheropteron was found in the 

 Cambridge Greensand of Swaffham. It had previously been 

 recorded from the Chalk-rock in this country. 



Cytheropteron cusjndatum, Jones and Ilinde, var. montuosa 



(Jones). 



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



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

 Cytheropteron cuspidatum, var. montuosa, Jones and Ilinde, 1890, 

 ' Suppl. Mon. Cret. Entom. p. 38, pi. iii. figs. 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 

 Swaffham. The previously recorded specimens were from 

 the Greensand of Warminster and the Antrim Chalk. 



Cytheropteron umhonatum (Williamson), var. acanthoptera 

 (Marsson). 



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



pomuiern und Riigen, p. 46, pi. iii. figs. 14«-c. 

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

 "and Ilinde, 1890, Suppl. Mon. Cret. Entom. p. 41, pi. i. figs. 11-13, 

 pi. iv. figs. 22-2!). 



This variety has not hitherto been found below the Chalk- 

 rock. The Cambridge-Greensand specimens show a marked 



