172 BRITISH COPEPODA. 



show a condition intermediate between the flattened 

 Peltidian group, on the one hand, and the typical 

 Harpacticids, such as Thalestris and Dactylopus, on 

 the other. 



As regards the generic term Idya, I think Boeck is 

 doubtless right in identifying Philippi' s genus with 

 Lilljeborg's Tisbe, and as the former has the claim of 

 priority it becomes necessary to discard the latter and 

 better-known name. 



1. IDYA FTJRCATA (Baird). PI. LXVII, figs. 111. 



Cyclops fur catus, Baird. Mag. ZooL and Bot., i, p. 330, t. ix, figs. 



2628 (1837). 

 Cyclopsina furcatus, Milne Edwards. Hist. Nat. Crust., iii, p. 429 



(1834). 



Canthocamptus furcatus, Baird. Brit. Entom., p. 210, tab. xxv, 



figs. 1, 2 ; tab. xxx, figs. 4, 5, 6 (1850). 



Nauplius furcatus, Philippi. "Weigmann's Archiv, p. 69 (fide 



Baird and Claus) (1843). 

 Tisbe furcata, Lilljeborg. De Crustaceis ex ordinibus tribus, 



tab. xxv, figs. 15, 11, 12, 17 (1853). 

 Clans, Die frei-lebenden Copepoden, p. 115, taf. xv, 

 figs. 1 10 (1863). Die Copepoden-fanna von 

 Nizza, p. 21, taf. iv, figs. 16, 17 (1866). 

 Tisbe ensifera, Fischer. Abhandl. der Konig. Bayer Akad., B. viii, 



p. 668, t. iii, figs. 6770 (1860). 



Idya furcata, Boeck. Oversigt Norges Copepoder, p. 34 (1864). 

 barbigera ? Philippi. Weigmann's Archiv (1843). 



Body elongated, pyrif orm ; anterior antennas (fig. 2) 

 slender, 8-jointed, first four joints (peduncle) consider- 

 ably stouter than the rest ; the comparative length of 

 the joints, though variable, may be stated as follows : 



1, 2, 3, 4, 5, 6, 7, 8. 

 10 18 13 8 3 3 2 8 



