KNOWN SPECIES OF MARINE OSTRACODA. 361 
their characters that it would be very satisfactory to be able without misgiving to 
place them in a distinct genus. But the characters which have been proposed for the 
genus Cythereis slide so insensibly, and through so many osculant forms, into Cythere, 
that I have found it almost impossible, in many cases, to determine to which genus a 
particular species ought to be referred. Cythere septentrionalis, C. costata, C. cristatella, 
&c., may be taken as examples of these debateable forms. Under these circumstances, 
there seemed to be but two reasonable courses open to me—either to reject the genus 
altogether, or to restrict it by some arbitrary line to the conspicuously fimbriated, 
spinous, and quadrilateral species so well represented by C. jonesii. I have chosen the 
latter course as being, on the whole, of the greater practical utility. A more perfect 
knowledge of the various species, and especially of the anatomy of the animals, will 
probably in time lead to a better classification. 
Order OSTRACODA, Latreille. 
Family CYPRIDA, Baird. 
Subfamily Cyruerinz, Dana. 
Genus Cytuereta, Jones (subgenus). 
Generic Characters.—‘‘ Animal unknown. Carapace oblong, compressed ; smooth or 
pitted ; no terminal denticulations: contact-margins of the right (larger) valve grooved 
or rabbeted on its inner edge for the reception of a flange presented by the contact- 
margin of the left (smaller) valve; both groove and flange stronger at the posterior 
than at the anterior portion of the valves.” Lucid spots arranged in a curved pinnate 
series on an oblong, obliquely placed depression near the centre of the shell. The 
depression appears internally as an elevation or tubercle. The number of the spots is 
from twelve to sixteen, and in shape they are linear-oblong, increasing in length towards 
the ventral margin. 
1. CyrHERELLA puLcHRA, n. sp. (PI. LVII. fig. 1, a—d.) 
Carapace elliptic-oblong. Dorsal and ventral margins nearly straight, parallel, slightly 
sinuated. xtremities rounded. Dorsal aspect ovate-oblong, compressed. Surface 
smooth, white. Lucid spots near the middle of the ventral half of the carapace, con- 
sisting of about sixteen linear-ovate spots arranged in a pinnate manner along a central 
curved line, the larger spots being nearest to the ventral margin ; the whole group is 
situated in a slight depression of the valves, and is very conspicuous also on the inner 
surface. 
Length 75 in. (6 mm.), 
Hab. Australia. 
VOL. V.—PART V. 3B 
