RECENT BRITISH OSTRACODA. 



443 



front, mucronate behind. Shell smooth or indistinctly reticulated. Central areola obso- 

 lete (" as in C. nigrescens^'' Sars). 

 Length in. 



Hab. In shell-sand from the River Ribble [Mr. E. C. Davison) and amongst oyster-ooze from Stram'aer 

 (G. S. B.), one specimen from each locality; Shetland [Mr. D. Robertson) . 



8. Cythertjua undata, G. O. Sars. (Plate XXXII. figs. 43-49, 66.) 



Cytherura undata, G. O. Sars, loc. cit. p. 75. 



humilis, Brady, Brit. Assoc. Report, 1866, p. 210. 



Scandinavian type ? Distkibution : Recent — Baffin^s Bay, Norway, Great Britain, Ireland. Fossil — 

 Glacial, Scotland, Ireland, Norway. 



Carapace of the female, as seen from the side, subrhomboidal ; greatest height equal to 

 rather more than half the length. Anterior extremity obliquely rounded, posterior ob- 

 liquely truncate, and forming a very short projection above ; superior margin arched, 

 inferior scarcely sinuated, and forming a distinct angle behind. Outline, as seen from 

 above, oblong, nearly parallel-sided, almost rectangular behind ; width equal to less than 

 half the length. The mcde rather more elongated. Shell thick and strong, indistinctly 

 reticulated, and marked with irregular crests or ribs, two or three of which usually run 

 directly forward from a transverse ridge in front of the middle of the valve, thus pro- 

 ducing the outline of the letter E. The surface-markings are usually more prominent in 

 the male than in the female. Colour yellowish. 



Length ^5- in. - - 



Hab. Birterbuy Bay, 10 fathoms, and in oyster-ooze from Stranraer (G. S. B.) ; Shetland, Cumbrae, 

 Macduff, and Oban {Mr. D. Robertson) ; the Minch {Mr. J. G. Jeffreys) ; Stornoway, and in rock- 

 pools, Arran, N.B. {Rev. A. M. Norman) ; Scarpa Flow, Orkney {Mr. E. C. Davison). 



9. Cytheuura piiODUCTA, n. sp, (Plate XXXII. figs. 60, 61.) 



Valves of the male, as seen from the side, oblong, produced into a rounded laterally 

 projecting ala ; height equal to less than half the length. Anterior margin rounded, 

 obliquely truncate below, posterior produced in the middle into a long tapering triangular 

 beak ; superior and inferior margins nearly straight in the middle, the latter forming 

 nearly a right angle behind. Outline, as seen from above, broadly ovate, widest in the 

 middle, greatest width equal to half the length ; extremities strongly mucronate. Surface 

 of the shell irregularly reticulate, polished, the ventral surface longitudinally striated. 

 Central areola broad, somewhat crescentic. The female is more tumid, perfectly smooth 

 and polished, without any sculpturing. 



Length 5^ in. 



Hab. Birterbuy Bay, 10 fathoms (G. S. B.) ; the Minch {Rev. A. M. Norman) ; off Ormeshead {Mr. D. 

 Robertson) . 



Apparently a scarce species, three specimens only having been met with from the first- 

 named, and one from the second locality. 



10. Cytheruua afeinis, G. O. Sars. (Plate XXXII. figs. 19-21.) 

 Cytherura affinis, G. O. Sars, loc. cit. p. 77. 



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