34 Mr. G. S. Brady on Ostracoda 



specimens found in the Scottish glacial clays. The descrip- 

 tion of them is therefore left for a '^ Monograph of the British 

 Posttertiary Entomostraca," which is now in preparation for 

 the Palaeontographical Society, by Messrs. Crosskey and 

 Robertson, in conjunction with the present writer. I have, 

 however, thought it desirable to give here figures drawn from 

 the recent Arctic specimens, the joint occurrence of these 

 (the only known recent specimens) being of very considerable 

 interest in connexion with their distribution in the fossil state. 



Cytheropteron pyramidalej nov. sp. (Plate V. figs. 11-14.) 



Carapace tumid, subpyramidal ; seen from the side, subrhom- 

 boidal, highest in the middle, greatest height equal to more 

 than half the length ; anterior extremity obliquely rounded, 

 posterior narrowed and produced in the middle : superior 

 margin very strongly arched, highest in the middle, and 

 sloping steeply towards each extremity ; inferior convex, 

 bending upwards behind. Outline, as seen from above, 

 subhexagonal, widest behind the middle, suddenly and 

 sharply acuminate in front, strongly mucronate behind; 

 width and height equal. End view triangular, sides very 

 slightly convex. Shell-surface marked with conspicuous 

 fossae, which are arranged in transverse curved rows ; ven- 

 tral surface sculptured with interrupted longitudinal furrows. 

 Length 4^ inch. 



Dredged by Messrs. Robertson and Crosskey in 25-30 

 fathoms, amongst mud, at Drobak, Christianiafiord. 



This species, though in general appearance approaching 

 very closely C. latissimum^ differs considerably in the propor- 

 tions of the carapace, being much more tumid when seen from 

 above ; the sculpturing of the surface is also much deeper and 

 more distinct, especially on the ventral aspect, and the sides 

 are less convex ; the contours are also altogether less rounded 

 than in its neighbom' species. 



Cytherura rudis^ nov. sp. (Plate V. figs. 15-17.) 



Carapace, seen laterally, subrhomboidal, nearly equal in height 

 throughout ; height equal to more than half the length : an- 

 terior extremity obliquely rounded, posterior produced in 

 the middle into an obscurely angular beak ; superior margin 

 very slightly arched, inferior almost straight : seen from 

 above, the outline is ovate, widest in the middle, sharply 

 pointed in front, mucronate behind ; greatest width equal to 

 half the length. End view subpentagonal, widest in the 

 middle ; the ventral surface concave, keeled in the middle. 

 Surface of the valves covered with rather large angular 



