44 Rev. A. M. Norman on new British Species of Ostracoda. 
larger than the others, and in size and appearance corresponds 
with a similarly situated tooth in Cyprideis torosa, and with that 
present in the left valve of Notodramas monacha (Cypris monacha, 
Baird). Possibly these teeth serve as guides to the right adjust- 
ments of the valves, and prevent the margin of the one from over- 
lapping the margin of the other too far when closed. 
The form of the carapace, when viewed from above, is ovate; 
and the valves (which are so tumid that the diameter and height 
are nearly equal) have their greatest convexity in the centre. 
The base, or ventral surface, is broad, rounded towards the ex- 
tremities, but in the centre hollowed out and flattened, giving 
the carapace a pinched-in appearance at that part. The front 
and hinder margins are produced internally into broad plates, 
these plates being channelled by a deep groove. 
Colour deep green. Length {4 inch; height <4, inch. 
This fine species may perhaps be most readily known by the 
peculiar pinched-in and flattened surface of the centre of the 
ventral margin; and this character is evident in all stages of 
growth. The young, as is usually the case among the Ostracoda, 
have the posterior extremity very much narrower in proportion 
to the anterior than is the case in more fully developed indivi- 
duals. The only British Cypris which equals the present species 
in size is C. clavata (Baird). 
I first found Cypris punctillata in the autumn of 1860, in the 
parish of Sedgefield, co. Durham, in a piece of clear water known 
as the Forge Dam. It was there associated with Alona quadrata; 
Peracantha truncata ; Pleuroxus trigonellus ; Cypris compressa, 
minuta, Westwoodi, and bistrigata (Jurine); Candona lucens and 
serrata (Norman) ; Cyprideis torosa, and other more common 
Entomostraca. During the past summer, I have met with it in 
extreme abundance in a second habitat—a pond about two miles 
distant from the first locality, where it lives in company with 
Daphnia Schefferi and other species. 
Cypris aculeata (Lilljeborg). Pl. II. figs. 7-10. 
Cypris aculeata, Lilljeborg, om de inom Skane forkom. Crust. af Ord. 
Cladocera, Ostracoda och Copepoda, p. 117, tab. 11. figs. 15, 16. 
Forma brevis et alta, .reniformis; margo dorsalis valde arcuatus, ad 
apicem rotundatum fere in medio situm assurgens ; margo ventralis 
leviter sinuatus. Forma desuper spectata elongato-ovata, antice 
angustior, acuminata. Latitudo maxima altitudine multo minor, 
pone medium sita. Basis convexa. Valvarum superficies aculeis 
arcuatis pilisque intermixtis admodum hispida, cellulis numero- 
sissimis excavata. Color ceeruleo-viridis. Long. 2, unc. 
Habitat regionem Dunelmensem prope Sunderland et Stockton. 
Carapace reniform, very high in proportion to its length, 
