104 



setae extending to the tip of the claws. Caudal rami almost straight and 

 gradually attenuated, apical claws slender, the distal one considerably exceed- 

 ing half the length of the ramus, proximal claw (the transformed dorsal seta) 

 nearly as long as the middle one. 



Male of somewhat smaller size than female, but resembling it in the general 

 shape of the shell, except that the posterior corner appears somewhat less pro- 

 duced and more evenly rounded off. Prehensile palps of maxillipeds of almost 

 equal size and only slightly differing in shape, propodos of left palp however 

 exhibiting at the end inside a rather conspicuous sinus not found on the right, 

 dactylus of the latter palp rather broader and more compressed than on the 

 left. Caudal rami considerably more curved than in female. Copulative appen- 

 dages strongly chitinised, of a more or less dark brown colour, with 2 of the 

 projecting lappets very conspicuous and somewhat spoon-shaped, the one issuing 

 from the lower face and curving anteriorly, the other from the upper face and 

 curving in the opposite direction, a 3rd lappet of a more simple shape extending 

 from the posterior end of the appendage. 



Colour in both sexes pale yellow, being in old specimens somewhat 

 darker, ochraceous. 



Length of adult female amounting to 1.70 mm., of male to 1.52 mm. 



Remarks. This is the only as yet known species of the present genus. 

 Its identity with the form recorded by Strauss was first settled by the preser 

 author in the year 1890 and has been admitted by all recent authors. Prt 

 viously this form had been described under 2 different specific names quote( 

 in the above given list of synonyms. 



Occurrence. I have taken this form, many years ago, rather abundantly 

 in some small ponds and ditches near Christiania, now destroyed by ne\ 

 building, and I have also met with this Ostracod in 2 other localities of our 

 country, wiz., at Moss and near Nevlunghavn, outside the Christiania Fjord. 

 The animals are rather active, svimming quickly about in the usual manner, 

 but never showing any attempt to the peculiar behaviour described above in 

 Notodrothas. Male specimens are not seldom found, but appear on the whole 

 to be more scarce than female ones. I have taken this form as late in the 

 year as in October, and it cannot therefore be considered to be an exclusive 

 vernal form, as believed by Dr. Aim. 



Distribution. Throughout Europe, North America (Turner). 



