from the u Cambridge Greenland." 343 



tumidity of the carapace, with a deep dorsal furrow and a 

 prickly surface, thus agreeing in all particulars with the 

 specimens found by Messrs. Jones and Hinde rather than 

 with those from Riigen. 



Two valves of this variety were found at SwafTham. 



Cytheropteron umbonatum (Will.), var. longispinata, 

 Jones and Hinde. 



Cy there umlonata, Marsson, 1883, Mittheil. naturw. Ver. Neu-Vor 



pommern unci Riigen, p. 4o, pi. iii. fig.*. 15 a-c. 

 Cytheropteron umbonatum (Will.), var. longispinata, Jones and Hinde, 



1890, Suppl. Mon. Cret. Entom. pp. 41, 42, pi. iii. figs. 11-13, pi. iv. 



figs. 30, 31. 



One specimen, with the spine damaged, was found in the 

 Cambridge Greensand at SwafTham. It has hitherto been 

 observed in the Gault of Folkestone, zones iii., iv., and v. 

 (Chapman and Sherborn) ; in the Chalk of Surrey and 

 Norfolk (Jones and Hinde); and in the White Chalk of 

 Riigen (Marsson). 



Family Cytherellidse. 

 Cytherella, Jones, 1849. 

 Cytherella ovata (Romer). 



Cytherina ovata, Romer, 1840, Verstein. nordd. Kreidegeb. p. 104, 



pi. xvi. fig. 21. 

 Cytherella ovata, Jones, 1849, Mon. Entom. Cret, p. 28, pi. vii. 



figs. 2-La-i; Jones and Hinde, 1890, Suppl. Mon. Cret. Entom. 

 • pp. 44, 4o, pi. iii. figs. 48-54, pi. iv. fig. 39. 



This widely distributed Cretaceous form has been found in 

 this country in the Gault at Folkestone, occurring in all the 

 zones, the Cambridge Greensand, and upward through most 

 of the beds to the top of the Chalk. It is one of the com- 

 monest forms of the Ostracoda in the material from SwafTham. 



Cytherella obovata, Jones and Hinde. 



Cytherella obovata, Jones and Hinde, 1890, Suppl. Mon. Cret. Entom, 

 p. 46, pi. iii. figs. 4G, 47. 



C. obovata was originally described from the Chalk of 

 Kent, and it has since been found in other strata at different 

 localities, notably from the Chalk-marl of Arlcsey, the base 

 of the Upper Chalk at Southerham, and the Micraster Chalk 

 of Swanscombe. 



Four separate valves were found in the Cambridge Green- 

 sand of Swarf ham. 



24* 



