596 Mr. F. Chapman on Ostracoda from the 



As a fossil it is known from the Wey bourn Crag and from 

 most deposits of post-Pliocene age. It is common in the 

 " freshwater bed " at Hitchin. 



Candona Candida (0. F. Miiller), var. tumida, Brady and 

 Kobertson. (PI. XV. figs. 22, 23.) 



Candona Candida (Miiller), var. tumida, Brady and Robertson, 1«70, 

 Ann. & Mag. Nat. Hist. ser. 4, vol. vi. p. 16, pi. ix. figs. 13-15 ; 

 Brady and Norman, 1889, Sci. Trans. K. Dubl. Soc. ser. 2, vol. iv. 

 p. 99, pi. X. figs. 14-17. 



This variety has been found commonly in rivers and dykes 

 subject to tidal influence. It differs from the typical species, 

 so common in fresh water, in the shortness and the tumidity 

 of the carapace. Another distinguishing character is the 

 rosette-like arrangement of the muscle-spots, and this is 

 clearly seen in at least one of the valves from Hitchin. The 

 variety is somewhat rare in that deposit. 



Candona Candida (0. F. ^Miiller), var. claviformis, 

 Brady and Norman. (PI. XV. figs. 24, 25.) 



Candona Candida (Miiller), var. claviformis, Brady and Norman, 1889, 

 Sci. Trans, li. Dubl. Soc. ser. 2, vol. iv. p. 99, pi. x. tigs. 1, 2. 



riiis variety was taken in the living condition from canals 

 and ponds. 



In the Pleistocene of Hitchin this variety is not unfrequent. 



Family Darwinulidae. 



Genus Darwinula, Brady and Kobertson. 



Darwinula Stevensoni, Brady and Robertson. 

 (PI. XV. figs. 26, 27.) 



VoJycheles Stevensoni, Brady and Robertson, 1870, Ann. & Mag. Nat. 



llist. ser. 4, vol. vi. p. 25, pi. vii. figs. 1-7, pi. x. figs, 4-14, 

 Darmnella Stevensoni, Brady, Crosskey, and Robertson, 1874, Post-lert. 



Entom. p. 141, jtl. ii. figs. 13-17. 

 Darxcinula Stevensoni, Brady and Norman, 1889, Sci. Trans, li. Dubl. 



Soc. ser. 2, vol. iv. p. 122, pi. x. tigs. 7-13, pi. xiii. tigs. l-9„pl. xxiii. 



fig. 6. 



It is of much interest to note the occurrence of this species 

 from Hitchin, since in the living state it is a characteristic 

 form in the East-Anglian Fen district ; and it is also found 

 in rivers, lochs, and canals in various parts of the British 

 Islands. 



Several separate valves of D. Steveruoni were found in the 

 Pleistocene deposit at Hitchin. 



