THE TERTIARY FORMATION. 19 



numerous, compressed between the laminae of the clay. Casts of valves possibly 

 referable to the same species were collected by the late Rev. H. M. de la Condamine. 

 f.g.s., of Blackheath, in the Planorbis-bed at Counter Hill, near Lewisham. 



No. 4. Candona Candida. 1 Mutter. Plate I, figs. 8 a — 8/, 5 a, 5 b. 



Cypris Candida, Mailer. Entom., p. 62, t. 6, figs. 7 — 9. 



Monoculus candidus, Jurine. Hist, des Monocles, p. 176, t. 19, figs. 7, 8. 



Cypris lucens, Baird. Trans. Berwick Nat. Club, i, p. 100, t. 3, fig. 15. 



— Candida, lb. Mag. Zool. Bot., ii, p. 134, t. 5, fig. 3. 



— — Zaddach. Synops. Crust. Pruss. Prodomus, p. 38. 

 Candona Candida, Baird. Trans. Berwick Nat. Club, ii, p. 153. 

 Cypris pellucida, Koch. Deutschland's Crust., &c, xi Heft, t. 5. 



— lucida (?), lb. Deutschland's Crust., &c, xxi Heft, t. 18. 



Candona lucens, Baird. Hist. Brit. Entom., p. 160, t. 19, fig. 1. [Adult female.] 



— — Jones. Annals and Mag. Nat. Hist., vi, p. 26, t. 3, fig. 8. 



Cypris pellucida, S. Fischer. Ueber das Gen. Cypris, &c, p. 148, t. 5, figs. 1 — 4. 



[Female.] 

 Candona Candida, Liljeborg. De Crustaceis, &c, p. 127, t. 11, figs. 19, 20; t. 25, 



figs. 13—15. 



INCH. 



Length, -fe Recent : England ; Europe. 



Post-tertiary: Forfarshire; Berkshire; Cambridgeshire; and Essex. 

 Pleistocene : Essex. 



Carapace rather large, long kidney-shaped, somewhat cylindrical, smooth, shining 

 (pearly white in the recent state ; often milky white when fossil) ; beset with scattered 

 pedicles of setce (and fringed with hairs, when recent) ; posterior portion larger than 

 the anterior, in the adult female curving boldly backwards and downwards, and termi- 

 nating in a blunt point (injured in the lithograph, fig. 8 a) ; dorsal margin arched, 

 especially behind ; ventral margin more or less incurved. Lucid spots six in a group, 

 forming a transverse, curved, front row of four, with two other spots behind the lowest 

 two of the front row (System b), figs. 8 e, 8/; this arrangement is subject to a varia- 

 tion, by which the lower five spots in the two rows lose their linear regularity (fig. 5 b), 

 and sometimes become so obliquely arranged as to converge into a radiate figure, 

 forming a star or rosette, accompanied by the upper isolated sixth spot, as seen in the 

 fragment of a valve, fig. 5 a. 



1 Zenker (1854), op. cit. p. 76, refers to this species as a Cypris, with the following synonyms : 



Cypris Candida, Mailer; C. compressa, Koch; C. pellucida, lb.; C. pubescens, lb.; 

 C. pellucida, S. Fischer; C. pigra, lb.; C. compressa, lb. 



