592 Mr. F. Chapman on Ostracoda from the 



For the material from which tlie species liere enumerated 

 l)ave been extracted I am indebted to Prof. T. Rupert Jones, 

 F.K.S., who had received it from Mr. W. Ilill a long time 

 ago. This present list contains only one species which I 

 have not myself found, and nine species and varieties are now 

 added to the earlier records. 



The bed containing the Ostracoda here under notice lies 

 upon a bed of gravel, and is itself overlain by a bed of brick- 

 earth 20 feet thick. It is a " soft calcareous loam, of a light 

 colour, from brown to almost white, which has been found, in 

 other parts of the brickfield, to pass down into a dark grey or 

 almost black deposit, fairly evenly stratified " *. 



Besides the Ostracoda, this deposit contains numerous 

 stems and fruits (oogonia) of Chara, eleven species of Mol- 

 lusca, and the remains of bear, deer, and rhinoceros. Further 

 details of this and the associated beds are to be found in the 

 Proc. Geol. Assoc. 1896 f, the locality having been visited 

 by the members of the above association during their excur- 

 sion to Hitchin. 



The sample of marl examined was exceedingly rich in 

 Ostracod valves ; they are very fragile and require some care 

 in the extraction. The process of washing the marl and 

 separating the organisms is best carried out by submerging a 

 sieve, containing some of the marl, under water, the sieve 

 having meshes line enough to retain the minute fossils, and 

 from time to time agitating the sieve vertically as well as in 

 a hoiizontal and circular direction. 



The following is a descriptive list of the Ostracoda from 

 the dejjosit at Hitchin as far as at present known. For 

 valuable help in the writing of this account I tender my 

 sincere thanks to Prof. Rupert Jones, F.R.S. 



Family Cyprididae. 



Genus Cyclocypris, Brady and Norman. 



Cyclocypris Iccvis (O. F. Miiller). 

 (PI. XV. figs. 1, 2.) 



Ctjpris lavis, Miiller, 1785, Entomostraca, p. 52, pi. iii. figs. 7-9. 

 Alonoculus ovum, J urine, lc>29. Hist, des Mouucles, p. 17'J, iJ. xix. 



tigs. 18, 19. 

 Ci/jjris vviivi, Jones, 1850, Monopr. Tert. Eutom. p. 14, pi. i. figs. 4 a, 6 ; 



JJradv, Crost^kev, and liobertsou, 1874, Monogr. rust-tert. Eutom. 



p. 125, pi. i. figa. -20 -SI. 



* Proc. Geol. Assoc, vol. xiv. p. 41G. 

 t Vol. xiv. pp. 415-419. 



