RECENT BRITISH OSTRACODA. 



415 



sinuated in front of the middle. " The shell is closely punctate and divided (especially 

 in the male) into large polygonal areolae. " Colour deep blackish green towards each 

 extremity, with an obliquely transverse white median band. Last joint of the upper 

 antennae elongated, equal in length to the preceding; second joint of the last pair of feet 

 much longer than the two following joints; terminal claw curved toward the apex. 

 Copulative organs of the male large, basal portion subquadrangular, with a very long 

 convoluted tube, distal portion obtusely rounded below, divided behind into many irre- 

 gular processes, of which the lower is large and obtusely pointed." 

 Length -jj in. 



The only specimen of C. glbba which I have seen is a female, in the collection of the 

 Rev. A. M. Norman. The locality in which it was taken is unknown. 



13. Cythertjra corntjta, n. sp. (Plate XXXII. figs. 12-15.) 



Distribution : Recent — Britain, Dardanelles. 



Carapace of the female, as seen from the side, subquadrangular, nearly equal in height 

 throughout; height equal to half the length. Anterior extremity broadly rounded, pos- 

 terior produced above the middle into a large obtusely rounded beak ; dorsal margin 

 gently arched ; ventral abruptly sinuated in front, produced behind into a sharply defined 

 crest, which terminates in an acute triangular lamina or spine. Outline, as seen from 

 above, somewhat hastate, broadest behind the middle, pointed in front, strongly mucro- 

 nate behind ; greatest width equal to more than half the length. End view triangular, 

 nearly equilateral, base flat and produced at the angles. The shell is faintly sulcate in 

 the middle, the anterior portion marked with almost obsolete polygonal depressions, tin 

 posterior irregularly reticulated ; ventral surface longitudinally striated, waved. 



Length -^ in. 



Hab. Birterbuy Bay, 10 fathoms, amongst mud (G. 8. B.); Cmnbrac and Shetland (Mr. D. Roberta) ; 

 Loch Erribol (Mr. D. 0. Drewetf) . 



0. cormta is evidently nearly allied to the preceding species, but is distinguished by the 

 acutely angular ventral ala, the less rounded outline, more prominent posterior beak, 

 weaker reticulation of the-surface, and, lastly, by its larger size. From 0. acuUcostctc .t 

 is separated chiefly by the character of the surface-markings. 



H. Cythertjra actticostata, G. 0. Sars. (Plate XXXII. figs. 1-11.) 



tytherura acuticostata, G. O. Sars, he. eit. p. "6. • 



Atlantic type. D, s t R , BOT .o, : iW-Norwav, Groat Britain, Irdaud. B«*-Kon»y, gl-a, 



Carapace of the female very tumid; seen from the side ^™^^ 



height somewhat eieding half the .length; broad y ^^tZ^ 

 waved, obliquely truncate, and produced above the middle n»i 

 superior niacin gently arched, slightly depressed ^j££*£~5{ 

 and terminating behind in an acute angular V^JJT£ e-th. The m* more 

 ovate, nrucronate behind , width equal ta^JJ^ more distiBctl y 

 elongated, lusher in front than behind, the superior ana uuci o 



