REPORT ON THE OSTRACODA. 87 



seen from left side, h from above, c from below, d from front. Magnified 60 

 diameters.] 



43. Cijthere pohjtrema, G. S. Brady (PI. XXI. fig. 5, «-/;). 



Cijtliere polijtrsma, Brady, Trans. Zool. Soc, 1878, vol. x. p. 393, pi. Ixvi. fig. 1, a-d. 



Shell of the female, seen from the side, subquadi-angular, highest in front, the height 

 over the hinge-joint considerably exceeding half the length ; anterior extremity broad, 

 well rounded, and bearing a series of from six to ten stout, blunt spines ; posterior 

 truncated, angular, and bordered irregularly with spines like those of the anterior 

 margin ; dorsal margin sloping backwards with a somewhat sinuous curve, but in the 

 male often much cut up and indented ; ventral margin more or less sinuous and spinous 

 at the hinder end ; the dorsal aspect is not unlike that of Cythere stimpsoni, except that 

 the lateral margins, instead of being straight, are convex ; end view also like Cythere 

 stimpsoni, but showing the projections of the ribs more strongly; the surface of the shell 

 is roughly excavated as in Cythere stimpsoni, and the lateral aspect of the valves shows 

 two very strong and almost straight longitudinal ribs, which terminate abruptly both in 

 front and behind without reaching the extremities of the shell. Length, l-33d of an 

 inch (77 mm.). 



A few detached valves brought by the Challenger from ofi" Prince Edward's Island in 

 the Southern Ocean are in no respect distinguishable from the fossil specimens described 

 by me in a Monograph of the Fossil Ostracoda of the Antwerp Crag, under the name 

 Cythere polytrema. It is extremely interesting to note the occurrence, alive in this 

 distant region, of so well marked a European fossil. The forms figured at d and e are, I 

 think, undoubtedly the right and left valves of the male, while/, g, and h represent most 

 likely immature conditions of the shell. 



[PL XXI. fig. 5, a-h. a Left valve of female seen from the side, b from above, c from 

 front, d left valve of male, e right valve of male ; /, g, k immature forms of the shell. All 

 magnified 45 diameters.] 



44. Cythere sccdaris, n. sp. (PI. XXI. fig. 8, a-c). 



Valves, seen from the side, much higher in front than behind, greatest height equal 

 to considerably more than half the length ; anterior extremit)^ broad and rounded, 

 armed with numerous long and stout spines which are dnected somewhat downwards ; 

 posterior extremity narrowed, angular, and irregularly sjsinous ; dorsal margin sloping 

 steeply backwards in a succession of very sharply angular steps ; ventral irregularly 

 sinuous, and bending upwards at the hinder end ; dorsal aspect ovate, with very 

 irregularly indented and spinous margins. Surface of the shell bearing one or more 

 much contorted longitudinal ribs, and covered, like the foregoing, with closely-set, 

 large, polygonal excavations. Length, l-30th of an inch ('85 mm.). 



