J94 

 94. Cythereis echinata, G. O. Sars. 



Cythereis echinata, G. O. Sars, Oversigt af Norges marine Ostracoder, p. 44. 



Syn: Cythere catenala, Brady. 

 irpex, Brady. 



monacantha, Brady. 



Specific Characters. Female. Shell rather clumsy and tumid, seen 

 laterally, broadly oval in shape, slightly higher in front than behind, greatest 

 height about equal to 3 /5 of the length, dorsal margin projecting in the ocular 

 region to a very distinct gibbous prominence, immediately behind which it 

 appears slightly concaved, thence gently arched and joining the hind edge 

 without any intervening angle, ventral margin scarcely at all sinuated, being 

 slightly convex behind, anterior extremity broady rounded, posterior rather 

 narrower and obtusely blunted, with the lower corner evenly rounded off; 

 seen dorsally, broadly ovate in outline, with the greatest width somewhat behind 

 the middle and exceeding half the length, side-edges evenly curved, anterior 

 extremity gradually narrowed to an obtuse point, posterior broader and more 

 blunt at the tip. Surface of valves evenly convex and everywhere armed with 

 numerous sharply pointed spines, those on the anterior edges pretty regularly 

 disposed, those on the posterior extremity somewhat unequal, 2 or 3 of them 

 at the infero-posteal corner being rather stronger than the others; sculpture 

 rather feeble, in the form of slightly defined areolae arranged somewhat concentri- 

 cally. Eyes apparently quite absent. Anterior antennae with the terminal joint 

 much prolonged, being fully as long as the 2 preceding joints combined. 

 Posterior antennae very slender, with the penultimate joint remarkably long 

 and narrow, apical claws much elongated; flagellum however rather short. Legs 

 slender, and rapidly increasing in length posteriorly. 



Male resembling the female in the general appearance, though having 

 the shell comparatively somewhat more elongated, with the dorsal margin more 

 distinctly concaved in front. Flagellum of posterior antennae still more reduced 

 than in female, being both shorter and thinner. Copulative appendages with 

 the basal part rounded triangular in shape and not at all produced below, but 

 armed in front with a small dentiform projection; terminal part comparatively 

 large, broadly oval in shape and not obviously produced either in front or behind. 



Colour of shell dark fuscous gray. 



Length of adult female 1.20 mm., of male 1.25 mm. 



Remarks. This is a very distinct and easily recognisable species, being 

 well distinguished from the other known members of the present genus by the 





