L 



H 



o-6o 



o-33 



o-59 



o-33 



072 



o-37 



o-59 



o-33 



0-63 



o-37 



58 EARLY TERTIARY OSTRACODA 



developed spines superimposed on reticulations ; ventral ridge and posterodorsal 

 process well-marked. 



Figured specimens. Io. 4253-7. 



Material. 8 specimens from Grignon, Paris Basin, from the Lutetian IV (sample 

 no. CAB 1002, Keij 1957, p. 19). 5 specimens from Villiers-St. -Frederic, Paris 

 Basin, from the same horizon. 



Type locality. Grignon, Paris Basin. 



Type horizon. Lutetian. 



Dimensions (mm). 



Io. 4253 Left valve 



Io. 4257 Left valve 



Io. 4254 Left valve 



Io. 4255 Right valve 



Io. 4256 Right valve 



Comparison. This species shows some affinity to Phalcocythere retispinata sp. nov. 

 but has a more spinose surface, less tapering carapace and a better developed 

 subcentral-tubercle. Further, P. horrescens has straight postero ventral margin in 

 the right valve, different posterodorsal process and less prominent eye-tubercle which 

 lies below and slightly posterior to the anterior cardinal angle. 



Remarks. The present species has been redescribed by Keij (1957) in detail, 

 where, although he ascribed it to the genus Hirsutocy there, he noted that it lacked the 

 very wide duplicature of that genus. 



Adult specimens vary in size. According to Apostolescu (1955, p. 272), they 

 range from 0-52 mm. to 0-70 mm. in length. 



Phalcocythere improcera sp. nov. 

 (Plate 30, figs. 7-12 ; Plate 31, figs. 1-4) 



Derivation of name. Latin, improcerus, short ; with reference to the carapace. 



Diagnosis. A small Phalcocythere in which the prominent ventral ridge possesses 

 an alar expansion ; posteroventral margin slightly protracted towards the venter, 

 subcentral-tubercle prominent. 



Holotype. Io. 4344, a male carapace (PI. 31, figs. 1, 2 ; PI. 30, figs. 8, 9). 



Paratypes. Io. 4296 + Io. 4258-9. 



Material. 68 specimens from the Sor Range Section from four horizons (sample 

 nos. 460-i, 460-j, 460-I and 460-n). GSP BM 2570-1. 



Type locality. Sor Range section. 



Type horizon. Upper Palaeocene, sample no. 460-i. 



Description. Carapace subrectangular in the male dimorph and sub-quadrate 

 in the female. Sexual dimorphy is rather marked ; the males are longer in proportion 



