EUCYTHERE— KRITHE. 183 



EucYTHERE Argus {G. 0. Sars). Plate X, figs. 12 — 15. 



1865. Cytheeopsis Aegus, Sars. Overs. Norg. mar. Ostrac, p. 58. 

 1868. EucYTHERE — Brady. Monog. Rec. Brit. Ostrac, p. 431, pi. xxvii, 



figs. 49—51. 



Carapace of the female, as seen from the side, oblong, subreniform, higher in front 

 than behind, greatest height in the middle and slightly exceeding half the length; 

 anterior extremity broadly, posterior narrowly rounded ; superior margin boldly arched ; 

 inferior sinuated in the middle. Seen from above, ovate, widest behind the middle, 

 greatest width equal to half the length, obtusely pointed in front, rounded behind. 

 Shell-surface smooth and polished, thickly set with large circular white papillae or 

 tubercles, which are often dotted in the centre. Shell of the male more compressed ; 

 seen from the side, subcuneiform, superior margin highest in front of the middle, 

 thence sloping steeply and almost in a right line backwards ; inferior margin perfectly 

 straight. 



Length, ^th of an inch. 



Distribution. Becent. — Norway, Great Britain, Ireland, Gulf of St. Lawrence. 



Fossil. — Scotland : Duntroon, Loch Gilp, Kyles of Bute, Kilchattan, Cumbrae, 

 Dumbarton, Cartsdyke, Paisley, Dalmuir, Old Mains, Elie, Drip Bridge. South Wales : 

 new Dock Basin at Cardiff. Ireland : Portrush. Norway and Canada : Post-tertiary 

 beds. 



Genus 5 — Krithe, Brady, Crosskey, and Bohertson} 



Valves thin and pellucid, subovate, truncate behind; smooth and shining, and set 

 with very small distant papillae. Hinge-joint simple, formed by a slight projection of the 

 left valve, which is received into a corresponding depression of the right. Upper antennae 

 very stout, five-jointed, the first two joints much thickened, the last three short and 

 bearing long curved spines ; lower antennae four-jointed. Mandibles small, with 



1 Kpi0i7, a barley-corn. The name Ilyobates was applied by G. 0. Sars in 1865 to this genus; 

 but, as the same term had been used by Kraatz (' Naturgeschichte der Insecten Deutschlands ') in 1858 

 to designate a genus of Coleoptera, it has become necessary to adopt a fresh name. 



