106 MR. G. 8. BRADY ON SPECIES OF 
Valves elongated, broad anteriorly ; upper margin arched 
highest a little in front of the centre, and with a slight 
gibbosity, from which it slopes gently backward; inferior 
margin sinuated ; extremities rounded, the posterior being 
much the narrowest. Valves sculptured with a reticu- 
lated pattern, giving somewhat a scaly appearance to the 
surface. Seen from above, the carapace is broadly oval 
in form, with pointed extremities. Colour olive-grey or 
brown. Length ~é8, inch; height +22, inch. 
This species is easily distinguished by the peculiar sculpturing 
of the valves, which, in fine specimens and with good illumina- 
tion under the microscope, resembles an exquisitely wrought 
pattern of silver filagree-work. The reticulations of which the 
ornament is composed are largest toward the extremities of the 
valves : across the middle of the carapace they are not very con- 
spicuous, as the shell-structure is there much more condensed. 
The junction of the open work of the extremities with that of the 
closer central band is shown in Pl. II. fig. 7. It will be seen 
that, though very much compressed, the tendency to a radiate 
arrangement of the lacune (?) is continuous throughout. 
I first found this species in a pond at Fenham, near Newcastle, 
in Apvil of the present year; and it has since been taken by the 
Rey. A. M. Norman in two ponds near Sedgefield, county Dur- 
ham, and again by myself near Whitburn, in the same county. 
Genus CANDONA, Baird. 
CANDONA VIRESCENS, n. sp. (PI. IIL, figs. 1-5.) 
Carapace elongated, compressed, rather higher in front than 
behind ; ventral margin slightly sinuated ; dorsal margin 
very gently arched; anterior and posterior margins 
rounded. Surface of the valves smooth. Seen from 
above, the carapace is compressed, widest in the middle, 
and tapering gradually toward the extremities. Coloura 
delicate sea-green, irregularly variegated with markings 
of alighter hue. Filaments of superior antenna five long 
and seven short. Length ,33, inch; height ;)4, inch. 
This species was found in considerable abundance in a shallow 
