49 



hairs. Eye comparatively large and very conspicuous in fresh specimens. 

 Caudal rami slightly tapered distally, and exerted at the end, in front of the 

 apical claws, to a digitiform process carrying a short deflexed bristle, distal 

 seta of the dorsal edge rather coarse, fully attaining the length of the apical 

 claws, the latter subequal in size. 



Male of somewhat smaller size than female, and slightly differing in the 

 shape of the shell, which appears comparatively shorter and stouter. Prehensile 

 palps of maxillipeds with the propodus o51ong oval in form and provided near 

 the end inside with a short spine accompanied by 2 unequal bristles, dactylus 

 much curved and somewhat narrower on the left than on the right palp. 

 Copulatory appendages of moderate size, oblong oval in shape and blunted 

 at the end, without any, lateral lappets, but giving origin on the inner face 

 to a freely projecting highly chitinised apparently tubular string, abruptly bent 

 near the base and somewhat surpassing the terminal edge of the appendage. 



Colour whitish, with a rather conspicuous dark brownish pigmentary patch 

 extending along each valve below its centre, and generally also with some 

 patches of the same colour at each extremity. 



Length of adult female 0.70 mm, of male 0.62 mm. 



Remarks. It is very probable that one or other of the Mediterranean 

 species recorded by G. W. Miiller may prove to be identical with the present 

 form; but as these species have chiefly been characterised only by some slight 

 differences in the form and extension of the spermatic vessels of the male, 

 and these differences cannot be asserted except in quite fresh and still living 

 specimens, I am at present unable to decide the identity with full certainty. 

 In the shape of the shell the form named P. mediterranea seems to come nearest 

 to the present species and may perhaps in fact be identical with it. 



Occurrence, I have met with this little beautiful Ostracod in several places, 

 both on the south and west coasts of Norway, and northwards up to the Lofoten 

 islands. . It is found in moderate depths on a muddy bottom, but nowhere in 

 any considerable number. The animal is a very habile swimmer, moving about 

 through the water rather speedily in the manner of the typical Cypridae, though 

 scarcely leaving the bottom for any longer distance. Male specimens are very 

 rarely met with. I have hitherto only come across 2 such specimens, the one 

 of which is figured on the accompanying plate. 



Distribution British Isles (Brady), Mediterranean (Norman), Cape Verde 

 Islands (Brady). 



Fossil in postglacial beds of Scotland. 



7 Crustacea. 



