594 Mr. F. Chapman on Ostracoda from the 



Genus Erpetocypeis, Bradj and Norman. 



Erpetocypris reptans (Baird). 

 (PI. XV. figs. 7, 8.) 



Cypris reptans, Baird, 1835, Trans. Benvicksbire Nat. Club, vol. i, 



p. 99, pi. iii. fig. 11. 

 Candona reptans, Baird, 1845, op. cit. vol. ii. p. 153 ; and Nat. Hist. 



Brit. Eutom. 1850, p. 160, pi. xix. fig. 3. 

 Oypris rej)tans, Brady, Crosskey, and Robertson, 1875, Mouogr. Post- 



tert. Entom. p. 128, pi. ii. figs. 31, 32. 

 Erpetocypris reptans, Brady and Norman, 1889, Sci. Trans. R. Dubl. 



Soc. ser. 2, vol. iv. p. 84, pi. xiii. fig. 27. 



E. reptans is a common British species and its European 

 distribution is wide. As a fossil it has been found in strata 

 as old as the Weybourn Crag. In the post-Tertiary bed of 

 Hitchin it is common and often of large size, some of the 

 valves measuring as much as 3'3 millim. in length. 



Genus Pionocypris, Brady and Norman. 



Pionocypris vidua (0. F. Miiller). 

 (PI. XV. figs. 9, 10.) 



Cypris vidua, Miiller, 1785, Entom. p. 55, pi. iv. figs. 7-9. 

 Cypridopsis vidua, Brady, 1868, Moncgr. Rec. Brit. Ostrac. p. 376, 



pi. xxiv. figs. 27-36, 46. 

 Pionocypris vidua, Brady and Norman, 1896, Sci. Trans. R. Dubl. 



Soc. ser. 2, vol. v. p. 720, pi. Lxiv. fig. 19. 



This species has been found as a post-Tertiary fossil in the 

 Fen district, and it is common as a freshwater form in 

 England and Europe generally. At llitchia this species is 

 not uncommon. 



Genus IlyoCYPRIS, Brady and Norman. 



Ili/oa/pris gihha (Ramdohr). 

 (PI. XV. ligs. 11, 12.) 



Cypris yihha, Ramdohr, 1808,Magaz. d. Gesellsch. naturforscb. Freuude 



zu Berlin, Quartal ii. p. 91, pi. iii. figs. 13, 14, 17. 

 I/yocypris yibha, Brady and Norman, 1889, Sci. Trans. R. Dubl. Soc. 



ser. 2, vol. iv. p. 107, pi. xxii. figs. 1-5 ; iid. ibid. 185KJ, vol. v. p. 727, 



pi. Ixviii. tigs. 20, 21. 



This species, well known as a recent form, is also known 

 from tlie Ilamstcad beds (Oligocene) of the Isle of Wight, 

 and it is common as a post-Tertiary fossil in England and 

 Scotland. 



At Hitchin only one well- differentiated specimen of /. gibha 

 was found, and in this the i)rincipal tubercle is prominent 

 and recurved. 



