14 Messrs. G. S. Brady and D. Robertson on the 
portion of the dorsal aspect, forming a T: —— 
sulcus when viewed from above. Length y in 
Hab. Rivers Deben and Scheldt, ea Water and Lake 
mera Somerton Broad and dykes on the site of Whittle- 
sea Mer 
The specimens from the last locality are doubtfully ae 
to the present species. C. fretensis is more nearly a t 
C. salina, Brady, than to any other British species, but differs 
from it in the less compressed and more distinctly ovate form 
of the carapace when seen from above, in the peculiar emargina- 
tion of the posterior margin, in the absence of the peculiar 
form of contact margin which distinguishes the valves of the 
latter species, as well as in other characters of form. We have 
not observed any colour-markings in this species; _ but those 
of C. salina are also sometimes observed to be wan 
Genus Cypripopsis, Brady. 
Cypridopsis (?) Newtoni, nov. sp. (P1. VII. figs. 14-16.) 
Carapace, as seen from the side, reniform ; greatest height in 
the middle, and equal to a little more than half the length ; 
extremities rounded, the anterior being the broader of the 
wo: superior margin boldly and evenly arched, inferior 
sinuated in the middle. Seen from above, compressed, 
ovate, acuminate in front, rounded behind; greatest width 
situated near the middle, much less than the height. Sur- 
face of the shell punctate, and covere with numerous ad- 
pressed hairs; colour dull green. Length 5*; inch. 
Hob. Rivers Nene and Cii and dykes on the site of Whittlesea 
Our « OPERUM of this species are not numerous, and we have 
not Loon successful in finding perfect specimens of the con- 
tained animal. The postabdominal rami are rudimentary, as 
in Cypridop ts; but the lower antennæ seem to be destitute of 
the setose brn ash, which in that genus is usually very long. 
The species would therefore appear to be an aberrant one; but, 
without a ‘iorough acquaintance with its internal structure, 
we think it best for the present to place it in the genus to 
which it is here assigned. It approaches closely in diesen 
appearance to Cypridopsis villosa and Potamocypris fulva; it 
is, however, larger than either, is more tumid, less strongly 
arcuate, and coarser in texture than the former ; whilethe almost 
equal and well-rounded valves, coarsely hispid surface, and 
ovate form when seen from above sufficiently distinguish it from 
the latter: it agrees very much with Fischer's figures of Cypris- 
prasina, but is more elongated and more densely hairy. 
