124 



Structure of the several appendages scarcely exhibiting any more pronounced 

 differences from that in C. salinus. 



Colour of the shell however very dissimilar, being uniformly light yellow- 

 ish, without any traces of the dark band-like patches adorning the shell of 

 that species. 



Length of adult female scarcely exceeding 1.20 mm. 



Male unknown. 



Remarks. The above-characterised form so closely resembles the pre- 

 ceding one, both in the general shape of the shell and in the structure of the 

 several appendages, that its specific distinctness might look somewhat questi- 

 onable, and indeed in his more recent publications Brady has withdrawn the 

 species, finding it undistinguishable from C. salinus. Yet, I think that these 

 2 forms ought to be kept apart, as they differ very conspicuously in the colour 

 of the shell, as also notably in habitat. On a closer comparison moreover some 

 slight differences are found to exist in the shape of the shell, as seen laterally. 



Occurrence. I have only met with this form in a single locality, viz., in 

 a ditche near Moss, where it occurred rather abundantly together with other 

 Entomostraca. The water in the ditch was perfectly fresh, and as the situation 

 of the ditch is considerably above the level of the sea, no mixture of salt 

 water can ever have taken place. Brady has found it under quite similar 

 conditions. 



Distribution. British Isles (Brady). 



Gen. 22. Heterocypris, Glaus, 1892. 



Generic Characters. Shell moderately tumid and more or less reniform 

 in shape, with the dorsal face not gibbously arched; its colour in all the known 

 species uniformly yellow. Valves conspicuously unequal, the left one being 

 the larger, and overlapping the right anteriorly as also somewhat ventrally; 

 edges of right valve roughly tuberculated along the anterior extremity and 

 along the posterior part of the ventral side. Structure of the several appe 

 dages ralher like that of the preceding genus. 



Remarks. This genus was proposed in the year 1892 by Glaus, to include 

 the well known European species Cypris incongruens Ramdohr. It has how- 

 ever not been admitted by subsequent authors, who regard it as identical with 

 the genus Cyprinotus of Brady, to which it certainly shows a close affinity. 

 Yet, I find it appropriate to keep these 2 genera apart, as they differ con- 

 spicuously in the shape and partly also in the structure of the shell. More- 



, 



