Ostracoda and Foraminifera of Tidal Rivers. 23 
waved, impressed with distant rounded punctures: lips of 
the valves much thickened and roun ed, those of the 
ventral surface somewhat depressed. Animal unknown. 
ength zy inch. 
Hab. Dredd in the river Cam at Ely. One specimen only 
taken. 
We have already mentioned en several Ostracoda and 
some fragments of other animals (Echinus-spines and shells of 
Balanus) were met with in our dredgings from the river Cam. 
The fragments of Echinus and Balanus must be regarded as 
fossil, and may have been derived either from some posttertia 
deposit or from the Gault. It becomes difficult under these 
circumstances, where the animal itself is absent, to decide 
which of the Ostracoda are recent and which fossil specimens ; 
but that from which our present description is taken is alto- 
gether so unlike a fossilized shell, being semitransparent, 
highly polished, and in almost perfect condition as regards the 
preservation of its spines and surface-markings, that we can 
scarcely doubt its recentness. If it be really so, it constitutes 
a most interesting addition to the wee not only by reason of 
its peculiar configuration, but of its occurrence in fresh water. 
The only known recent species at all nearly resembling it is 
C. Sorbyana, Jones (dentata, Sars), which exhibits the same dif- 
ferences in the form of theright and left valves, but differs greatly 
in general form. Some of the fossil specimens obtained in the 
river Cam belong to strongly spined and probably deep-sea 
species. But associated with them occurred examples of se- 
veral species usually found at the present ay living in estua- 
ries or in littoral marine situations : erede e regard as being 
of recent origin; they are as follows :—Pontocypris heus 
nella (2), Cythere Piden C. villosa, (. Pieter. (9), MÀ obit 
ridea torosa, var. teres, Loxoconcha elliptica, L. tamari 
Genus Loxocowcna, G. O. Sars. 
Loxoconcha pusilla, nov. sp. (Pl. VIII. figs. 1-3.) 
Carapace, as seen from the side, subrhomboidal, rues equal 
in height throughout ; ee CLE to half the ength ; ex- 
widest in the middle, extremities nearly acuminate, 
width considerably less than the lu Shell delicato and 
hairs and papille. Length =; inch. 
Hab. Montrose Basin, Firth of Forth; rivers Wansbeck 
Blyth, Deben, Ouse (Norfolk), and Scheldt, Searce in all 
these places, 
