83 



exhibiting numerous densely crowded areolae or pits, especially very sharply 

 marked in young specimens. Posterior legs with the penultimate joint distinctly 

 subdivided, shortest apical seta not hamiform and nearly twice the length of 

 the terminal joint. Caudal rami resembling in shape those in C. slagnalis, 

 though perhaps a little shorter. Genital lobes of moderate size and simply 

 rounded, not forming any projecting corner behind. 



Male of about same size as female and only slightly differing from it in 

 the shape of the shell. Prehensile palps of maxillipeds and copulative appen- 

 dages not essentially differing in structure from those parts in C. stagnalis. 



Remarks. I have felt justified in restoring the species originally established 

 by Brady as C. albicans, although that author in his more recent publications 

 has questioned its validity, supposing it to have been merely founded on 

 immature specimens of an earlier known Candona, C. compressa (Koch). True, 

 in very young specimens of this and also of some other Candonae a slight 

 areolation of the valves similar to that described by Brady in his C. albicans, 

 may be traced; but in none of them this areolation is so strongly marked as 

 in this species and very soon disappears wholly by the growth of the animal. 

 In the present species, however, it is well observable also on the valves of 

 fully adult specimens, though somewhat less conspicuous than in the immature 

 state. I have compared young specimens of the present species with the 

 description and figures given by Brady, and find the agreement quite complete, 

 both as to the shape of the shell and to its sculpture. The C. parallela of 

 G. W. Muller is unquestionably identical with Brady's species. 



Occurrence. This form is rather common in the environs of Christiania, 

 being generally found in small ditches and pools with muddy bottom. During 

 the early part of the summer, as a rule, only immature specimens are met with, 

 but somewhat later, under favourable circumstances, also fully adult animals 

 may be captured. Male specimens seem to be rather scarce. I have as yet 

 only come across 2 such specimens, the one of which is figured on the 

 accompanying plate. 



Distribution. Sweden (Aim), British Isles (Brady), Germany (G. W. Muller). 



22. Candona compressa, (Koch). 



(PI. XXXIX, fig. 2). 



Cypris compressa, Koch, Deutschlands Crustaceen, p. 171, PI. 17. 

 S y n : Candona pubescens, Vavra (not Koch). 

 fallax, G. W. Mailer. 



Specific Characters. Female. Shell somewhat compressed, seen laterally, 

 angularly subreniform in shape, much higher behind than in front, greatest 



