region and sloping rather steeply behind, ventral margin almost straight, 

 anterior extremity broadly rounded, posterior much narrower and obtusely 

 truncated, with the upper corner well marked, the lower rounded off; seen 

 dorsally, oblong ovate in outline, with the greatest width behind the middle 

 and about equal to 2 /5 of the length, anterior extremity pointed, posterior 

 obtuse. Valves only slightly transparent, with a slight angular expansion 

 behind, near the ventral face; surface of a dull appearance, being marked 

 with closely set somewhat polygonal pits and a few small tubercles; marginal 

 zone well defined and crossed by somewhat distant pore-channels; edges clothed 

 with scattered hairs. Anterior antennae with the terminal part much longer than 

 the distal segment of the basal part, last joint very narrow and nearly as long 

 as the 2 preceding joints combined. Vibratory plate of mandibular palp edged 

 with 4 setae of unequal length. Last pair of legs with the terminal part more 

 than twice as long as that of 1st pair. Genital lobes comparatively large, 

 reniform in shape. 



Male. Shell considerably more elongate than in female, seen laterally, 

 oblong subreniform in shape, with the greatest height scarcely attaining half 

 the length, ventral margin distinctly sinuated in front of the middle, anterior 

 extremity somewhat deflexed. Copulative appendages with the basal part very 

 voluminous, oval trigonal in shape, and sending off below 2 blunt processes 

 curving forwards; terminal part very small and imperfectly defined from the 

 basal one, terminating in front in a short pointed lappet. 



Colour of shell grayish or pale fuscous. 



Length of adult female 0.58 mm., of maie 0.70 mm. 



Remarks. This form was recorded as early as the year 1868 by Brad 

 and was described the following year by the present author under the nam 

 of Cythere drammensis. The identity of this latter form with Cythere fuscata 

 was however not recognised by Brady, who erroneously referred it to anoth 

 nearly allied, but evidently different species viz., Cythere rubida Brady. Th 

 present species ought to be regarded as the type of the genus Cytherotnorph 



Occurrence. The only place where I have hitherto met with this form i 

 at Svelvik, entrance of the Drammen Fjord. It occurred here rather abundantl 

 in a short distance from the beach among algae, together with Leptocythere 

 castanea and a number of true fresh-water Entomostraca, the surface-water i 

 the Fjord being almost quite fresh by the afflux of the great Drammen rive 



Distribution. Gulf of Finland, Sweden, British Isles, Holland. 



Fossil. Scotland. 



