452 Mr. G. S. Brady on Recent Ostracoda 
situated near the middle: extremities broadly and evenly 
rounded. Hinge-margins somewhat depressed ; hinge-pro- 
cesses strongly developed. Surface of the shell smooth and 
polished, beset with more or less numerous circular punc- 
tures, each bearing a short rigid hair. Colour yellowish 
white. Length =, inch. 
all the localities. In Britain it is known only from the 
single (?) specimen described by Mr. Norman, which was 
taken in “very deep water" in Unst Haaf. Mr. Norman's 
description applies accurately to the American specimens, ex- 
cept in the matter of the ^ distant punctured papille." The 
ornamentation, it is true, does appear papillose in some lights; 
but this is, I think, an optical illusion: when carefully exa- 
mined, the seemingly elevated circles resolve themselves into 
coneave pits, each with a little central bristle. I have seen a 
eg fossil valve of this species:from the Scottish glacial 
clay. 
Cythere tuberculata, Sars. 
These specimens are much less rounded in outline and more 
rugged in general appearance than is usual with European 
specimens ; there is also a tendency, more or less pronounced, 
to the formation of one or more longitudinal ridges near the 
ventral border. But the distinctions do not seem sufficient to 
warrant the separation of the form as a new species. 
Cythere canadensis, nov. sp. (Pl. XIX. figs. 4-6.) 
middle: superior margin gently sloping, nearly straight, 
sinuated behind the anterior hinge; inferior margin also 
straight, excepting a slight median sinuation. Seen from 
above, somewhat lozenge-shaped, somewhat tapered toward 
front, more rounded behind, widest near the middle ; 
width equal to about two-fifths of the length; extremi- 
ties obtuse, subtruncate. Shell-surface uneven, irregularly 
pitted, marked with more or less prominent, flexuous, longi- 
tudinal ribs, and bearing usually a rounded central tubercle ; 
bordered in front, a little within the anterior margin, by a 
wide, elevated, and rounded ridge ; posterior margin having 
a similar but less conspicuous border. Length y's inch. 
