138 



sculptured with rather coarse rounded pits. Vibratory plate of maxillipeds 

 with only 2 setae. Caudal rami about as in P. vidua. 



Colour of shell uniformly greenish, without any dark patches across the 

 valves. 



Length of adult female 0.72 mm. 



Male unknown. 



Remarks. This species was recorded in the year 1869 by Brady and 

 Robertson, but was subsequently withdrawn by the same authors, being only 

 considered to be a variety of P. vidua, and this opinion has also been sanc- 

 tioned by the most recent author, Dr. Aim. Yet, the specific distinctness of 

 this form seems to me to be unquestionable, as it distinguishes itself, not only 

 in the shape and colour of the shell, but also in some of the structural details 

 (maxillipeds). The form recorded by Kaufmann as Cypridopsella tumida is 

 apparently identical with the present species. The reference of this form to 

 the genus Cypridopsella is quite unreasonable, being only founded on the 

 small number of setae on the vibratory plate of the maxillipeds. In all other 

 respects it shows itself as a true member of the present genus. 



Occurrence. I have only met with this form quite occasionally in some 

 shallow grassy swamps near Christiania. 



Distribution. British Isles, Germany, Switzerland, and probably many 

 other parts of Europe. 



58. Pionocypris elongata (Kaufmann). 

 (PI. LXIV, fifc. 3). 



Cypridopsella elongata, Kaufmann, Cypriden und Darwinuliden der Schweiz, p. 314, 

 PI. 19, figs. 14, 15; PI. 22, figs. 2023. 



Specific Characters. Female. Shell unusually elongated, seen laterally, 

 oblong oval in shape, greatest height a little in front of the middle and 

 scarcely exceeding half the length, dorsal margin quite evenly arched, ventral 

 slightly sinuated in the middle and conspicuously bowed in the oral region, 

 anterior extremity somewhat obliquely rounded, posterior narrower and obtuse 

 at the end; seen dorsally, oblong ovate in outline, with the greatest width 

 behind the middle and slightly exceeding half the length, anterior extremity 

 obtusely pointed, posterior rounded off. Surface of shell smooth and finely 

 hairy, without any obvious sculpturing. Left valve exhibiting, inside the anterior 

 edge, a row of very conspicuous rounded thickenings. Vibratory plate of 

 maxillipeds with only 2 setae. Caudal rami of the usual appearance. 



