1906-1907.] British Hydrachnid(Z : The Genus Fiona. 379 



straighter, and not spread out wide in the centre as we find 

 in the same segment of P. fuscata. 



Locality. — Catfield Fen, Norfolk Broads. 1904. 



3, Fiona Ncumani, Koen. 



Male. — About 0*80 mm. in length. Colour yellow, with 

 brownish markings on dorsal surface. Palpus thicker than 

 trochanter of first leg. Three swimming-hairs at distal end of 

 patella. Seminal pocket much broader than long. 12 to 

 15 acetabula on each plate. Three hair -pegs on fourth 

 segment of palpus. Male only as yet found in Britain. 

 (Plate XXXI., figs. 8-12.) 



Locality. — Norfolk Broads. 



4, Fiona ohttcrhans, Pier. 



Female. — About I'lO mm. in length, of a brownish-yellow 

 colour with dark-coloured markings, in some specimens nearly 

 black. Malpighian vessel often very indistinct. Legs, palpi, 

 aud all chitinous parts generally of a pale-blue colour. Palpi 

 strong, and having on the flexor edge of the fourth segment 

 two prominent hair pegs nearly side by side, about one-third 

 from distal end of fourth segment. The genital plates are 

 sickle-shaped, with from 18 to 25 acetabula each. There 

 are also from 1 to 5 acetabula free on the ventral surface 

 within the curve of the sickle-shaped plates. 



Male. — About 0"64 mm. in length. The third pair of legs 

 are each terminated by a strong claw (Plate XXXIIL, fig. 25). 

 There are three swimming-hairs at distal end of the patella of 

 fourth leg. The anus is placed so close into the bay of the 

 genital plates that, on first observation, it appears to be on 

 the plate itself. (Plate XXXIL, figs. 15, 16 ; Plate XXXIIL, 

 figs. 23-25.) 



Localities. — Common, 



5, Fiona disparilis, Koen. 



This is a species or variety very near to P. obturbans. Pier, 

 The female is larger, measuring as much as 1*30 mm, in 

 length. The genital plates are sickle-shaped, with from 50 to 



