REPORT ON THE OSTRACODA. 113 



Krithe, Brady, Crosskey, and Kobertson. 



Ily abates, G. 0. Sars, Oversigt af Norges marine Ostracoder, 1865. 



Krithe, Brady, Crosskey, and Robertson, Post -Tertiary Entomostraca of Scotland, &c., 1874. 



Valves thin and (except in old age) pellucid, subovate, truncate behind, smooth, 

 polished, and set with very small distant circular papillae. Hinge-joint simple, formed 

 Ijy a slight projection of the left valve, which is received into a corresponding depression 

 of the right. Anterior antennae very stout, five-jointed, the first two joints much 

 thickened, the rest short and bearing long curved spines ; posterior antennae four-jointed. 

 Mandibles small, with unusually long slender teeth ; palp three-jointed, the second joint 

 elongated, branchial appendage having one rudimentary and two long ciliated setas. 

 Maxillas of the usual form. Feet very short, the first two pans three-jointed, kxst pair 

 four-jointed ; " right foot of the last pair, in the male, prehensile and only three-jointed, 

 terminal claw very large and strong. Abdomen of the female very convex above, the 

 post-abdominal lobes bearing two short hairs." Eyes wanting. 



The members of this genus are at once recognisable by their smooth, ovate outline 

 and sharply truncated posterior extremity. Though widely distributed, the number of 

 specific forms does not appear to be large, and amongst fossU species I know of 

 none which can with certainty be referred here except Bairdia pernoides and Bairdia 

 kevissima, Bornemann,^ and two British Tertiary and Post-Tertiary species, Krithe barton- 

 ensis (Jones), and Krithe glacialis (B., C, and R.), the first-named of which occurs also 

 plentifully living in the British and Scandinavian seas. 



The generic name Krithe was proposed on account of the preoccupation of the w^ord 

 Ilyobates, applied by Sars to these animals in 1865. The anatomical details given in the 

 foregoing description are taken almost entirely from Sars' statement. I have myself had 

 scarcely any opportunity of examining the living animals. 



1. Krithe hartonensis, Jones (PI. XXVII. fig. 2, a-d). 



Cijtherideis lartonensU, Jones, Monog. Tert. Entom., p. 50, pi. v. tigs. 2, a, h; 3, a, h (1856). 



Ilyobates yretexta, G. 0. Sars, Oversigt Jforges Mar. Ostrac, p. 60 (1865). 



Ihjohates hartonetisls, Brady, Monog. Rec. Brit. Ostrac., p. 432, pi. xxxiv. figs. 11-14, pi. xl. fig. 5 



(1868). 

 Krithe hartonensis, Brady, Crosskey, and Robertson, Monog. Post-Tertiary Entom., p. 184, pi. ii. 



figs. 22-26 (1874). / 



Carapace elongated, subovate, in general outline not unlike a grain of wheat ; seen 

 from the side, the shell is oblong and subquadrangailar, the height being equal to about 

 one-haK of the length and nearly alike at all points ; the extremities are nearly equal in 

 height, the anterior evenly rounded, the posterior somewhat flattened, rounded ofi" at its 

 upper, and obscm'ely angular at its lower, termination ; dorsal and ventral margins 



' Die Mikroskopisclie Fauna des Septarienthones von Hermsdorf bei Berlin (Zeitschr. d. deiltsch. GeoL, Ges., 1855). 

 (ZiOOL. CHALL. EXP. — PAET HI. — 1880.) C 15 



