SUPER-ORDER III OSTRACODA 645 
Cythere, Miller (Figs. 1342, 1343). Shell reniform or sub-quadrate, usually 
widest in front; surface 
ornamented with punctae, 
nodes, spines, and ridges ; 
hinge teeth strong, placed 
one at each end of a hori- 
zontal bar which fits into a 
corresponding furrow and 
sockets of the left valve. 
In the sub-genus Cythereis, 

Jones (Fig. 1344), the con- Fic. 1343. 
nectin bar of the hinge is < G Cythere Dunemelensis, Norman. 
5 s { = = SEM Se Pleistocene ; Jordan Hill, Eng- 
Ww anting. Cretaceous to Cythere Edwardsi, Roem. sp. land. A, Interior of left valve. 
Recent Miocene; Léognan, near Bor- B, Exterior of right valve, en- 
: deaux.  22/; (after Bosquet). larged (after Brady). 
Cytheridea, Bosq. (Fig. 
1345). Differs from Cythere in having hinge beset with row of small teeth in right 

Fia. 1344. 
Cythereis quadrilatera, Roemer. Gault; Folkestone. 2/; (after T. Rupert Jones). 
valve, often interrupted in the middle, and with corresponding pits in the left. Jura 
to Recent. 
Cytherideis, Jones. Shell more or less triangular. Surface 
smooth, pitted or tuberculate; hinge simple. Cretaceous to 
Recent. 
Family 4. Thlipsuridae. Jones. 

Minute, reniform, or ovate inequivalve shells, the margin of one 
valve overlapping that of the other more or less completely ; dorsal 
Cytheridea  Muelleri, eee) Ka poe ie eae aoe ee aCe De 
Miinst. sp. Eocene, Margin arcuate, ventral sometimes straight or slightly sinuate. 
Colwell Bay, England. Surface with two or more definite pits. 
22/) (after Jones). a 
Fig. 1345. 
Thlipsura, Jones and Holl. Each valve generally with three 
pits, one posterior and two in the anterior half. No ornament. Silurian. 
Octonaria, Jones. Differs from the last in having the surface of valves raised into 
a thin spiral or annular ridge which in more typical forms is 8-shaped. Silurian and 
Devonian. 
Phreatura, Jones and K. Distinguished from Thlipsura by the strong compression 
of posterior end of shell, which is further marked by a shallow semicircular pit; a 
similar but smaller pit present at anterior extremity. Carboniferous. 
Family 5. Cypridae. Zenker. 
Minute, mostly reniform or elongate-ovate, corneous or corneo-caleareous shells, with 
thin, somewhat unequal valves, one overlapping the other either ventrally or dorsally or 
both. 
Recent Cypridae are chiefly fresh-water inhabitants, but this is true in a lesser 
degree of the fossil forms. All the Palaeozoic representatives are marine, excepting 
