146 ON SPECIES OF OSTRACODA FOUND 
cells. The superior portion of the anterior extremity is margined 
with a row of eight spines; and the inferior portion of the pos- 
terior extremity in the right valve is margined with about five 
spines. The lowest of these posterior spines is considerably 
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 
overlapping 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 , 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, asis 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 Oypris punctillata in the autumn of 1860, in the 
parish of Sedgefield, in a piece of clear water known as the 
Forge Dam. It was there associated with Alona quadrangularis ; 
Peracantha truncata; Pleuroxus trigonellus ; Cypris compressa, 
minuta, Westwoodit, 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 at Layton, 
about two miles distant from the first locality, where it lies in 
company with Daphnia Scheffer: and other species. 
