190 



inity broadly and somewhat obliquely rounded, posterior much narrower and 

 almost transversely truncated, upper corner obtuse, lower a little more pro- 

 minent and rounded off at the end; seen dorsally, irregularly oblong in out- 

 line, with the greatest width about equal to 2 / 5 of the length, side-edges 

 somewhat bowed in front of the middle and slightly angular behind, both 

 extremities obtusely truncated, the posterior a little broader than the anterior. 

 Surface of valves with somewhat irregular and densely set pittings, less con- 

 spicuous than in the preceding species, and moreover marked with scattered 

 small tubercles, edges quite smooth and rather densely hairy in front and 

 behind. Hinge with the closing teeth very strongly developed. Anterior 

 antennae with the terminal joint somewhat prolonged, exceeding considerably 

 half the length of the preceding joint. Posterior antennae with the apical claws 

 rather slender, flagellum short and scarcely thickened in the middle. 



Male of about same size as female, but having the shell comparatively 

 narrower, with the dorsal margin perfectly straight. 2nd pair of legs slightly 

 transformed, the apical claw being abruptly curved and armed with about 8 

 thin spinules gradually diminishing in length distally. Copulative appendages 

 with the terminal part remarkably small, obtusely triangular in shape. 



Colour of shell dark fuscous brown, with the marginal zone lighter; limbs 

 bright yellow. 



Length of adult female 0.95 mm. 



Remarks. This form was recorded as early as the year 1856 by Jones 

 from fossil tertiary shells. It was subsequently observed by the present author 

 in the living state, and described under the name of Cythereis clavata. The 

 species is easily recognised from the other known forms of the present genus 

 by the very coarse and pronouncedly club-shaped shell. 



Occurrence. I have taken this form very abundantly in the upper part 

 of the Christiania Fjord at a depth of 7 12 fathoms, muddy bottom. It also 

 occurs in many other places on our coast up to Finmark. 



Distribution. British Isles, Gulf of St. Lawrence, Dawis Strait, Spitzbergen. 



Fossil. Norway, Scotland. 



92. Hemicythere oblonga, (Brady). 



(PI. LXXXVII, fig. 2), 

 Cythere oblonga, Brady, Trans. Zool. Soc. London, Vol. V, p. 373, PI. 59, fig. 5 a d. 



Specific Characters. Female. Shell somewhat tumid, seen laterally, rather 

 regularly oblong oval in shape, slightly higher in front than behind, greatest 



limbs 



