396 DE. G. S. BEADY ON THE OSTEACODA 



being in the shape, regularity, and degree of development of the spines. The spines 

 vary in shape from that of evenly rounded blunt teeth of regular size to that of long 

 and slender, or flat, squamous processes. In the best-developed recent specimens 

 (those especially from the North Sea) the first-named condition occurs, and the rows of 

 spines are arranged with much regularity ; in others (as for instance in many specimens 

 from the Mediterranean and in most of the fossil examples) the spines are less regular 

 in arrangement, and tend either to become few, long and slender, or flattened and squa- 

 miform : but there are all shades of gradation between these extreme types. The figures 

 in PL LXVII. are taken with great accuracy from a fine fossil specimen illustrating an 

 intermediate condition, but with rather a marked tendency to a squamous form of the 

 spines, except on the posterior margin. 



C. jonesii occurs in all the Antwerp beds except in that of Trophon antiquum, but 

 nowhere in much abundance. 



Ctthere lima, Reuss. 

 Cythere lima, Eeuss, Zeitschrift d. deutsch. geol. Ges. 1855, p. 280, t. x. fig. 7. 



One valve, referable apparently to this species, was found in the Panopcea-menardi 

 bed ; but, owing to,, its having been lost or mislaid, I am unfortunately not able to 

 describe it. 



Genus Cytheridea, Bosquet. 



Valves unequal, ovate or subtriangular, highest near the front ; smooth or marked 

 with scattered circular papillae, with impressed puncta or concentric furrows ; hinge 

 composed of two crenulated crests on one valve, which articulate with depressions of 

 the opposite valve. Upper antennae very robust, mostly 5-jointed, spmous; lower 

 4-jointed. Mandibular palp 3-jointed, and having a distinct branchial appendage. 

 Right foot of the first and second pairs of feet, in the male, different from the rest, that 

 of the first very strong and prehensile, of the second very feeble ; the apex rudimentary 

 and destitute of a terminal claw. Eyes distinct. 



Ctthertdea papillosa. Bosquet. 

 Cytheridea papillosa, Bosquet, Entom. fossil, terr. Tertiair. Prance, p. 43, pi. ii. fig. 5 (1853) ; 



Brady, Trans. Zool. Soc. Lond. (1865), vol. v. p. 370, pi. Iviii. figs. 8a-ff; Brady, Monog. 



Recent Brit. Ostrac., Trans. Linn. Soc. vol. xxvi. (1868) p. 423, pl. xxviii. figs. 1-6, pi. xl. fig. 1; 



Brady, Crosskey, and Eobertson, Monog. Post-tert. Entom. Scotland, p. 176, pl. vi. figs. 12-15 



(1874). 

 Cythere bradii, Norman, Nat.-Hist. Trans. Northumberland and Durham, vol. i. p. 15, pl. v. figs. 5-8 



(1865). 

 Cyprideis bairdii, Sars, Oversigt af Norges Marine Ostracoder, p. 53 (1865). 



Var. Iwvis. (Plate LXII. figs. 1 «-l d.) 



Carapace, as seen from the side, subovate, highest a little in front of the middle, 

 height equal to half the length ; anterior extremity broadly and evenly, posterior only 



