British Freshioater liar pact ids. 191 



longer than the short outer branches, and composed of two 

 s uh equal joints ', inner branches of the second, third, and 

 fourth pairs two-jointed, j^rs/^oi'/i^ small. 



Attheyella pygmcea (G. 0. Sars). 



1863. Canthocamptus pyqmcBus, G. 0. Sars, " Overs, indenl. Ferskv.- 

 Copep.," Vidensk.-Selsk. i Christiania Forhaadl. 1862 (Aftr.), p. 21. 



1880. Attheyella crypiorum, Brady, oj). cit. vol. ii. p. 60, pi. lii. 

 figs. 1-18. 



1893. Attheyella cryptorum, T. Scott, Eleventh Hep. Fishery Board 

 for Scotland, pt. iii. p. 225, pi. vi. figs. 21-31. 



This small species appears to be generally distributed and 

 of frequent occurrence in the inland waters of the British 

 Islands. It may be distinguished from the closely allied 

 species Attheyella Zschoklcei (Schmeil) by the long curved 

 terminal setse of the outer branches of the fourth pair of 

 thoracic feet and by the depressed opercular plates. 



Attheyella Zscholckei (Schmeil). 



1893. Canthocamptus Zschokkei, Schmeil, Copep. des Rhatikou-Ge- 



birges, pp. 31-36, Taf. iii. 

 1893. Attheyella propinrma, T. Scott, Eleventh Rep. Fishery Board 



for Scotland, pt. iii. p. 227, pi. vii. figs. 1-11. 



This species, which may readily be mistaken for the one 

 previously described, appears to have an equally extensive 

 distribution, but it is not so frequently met with. There are, 

 however, comparatively few of the Scottish lochs which I 

 have examined where it has been entirely absent. Mr. D. J. 

 Scourfield has taken A. Zschokkei near London. In this 

 species the terminal setse of the outer branches of the fourth 

 feet have not the long, slender, curved ends so characteristic 

 of A. fygmcea, but the opercular plate is more prominent. 

 Dissection shows, of course, other points of difference, but the 

 differences just referred to may be seen without dissection 

 and with the aid of a hand-lens. 



Attheyella Duthiei^ T. & A. Scott. 



1895. Attheyella Duthm, T. & A. Scott, Ann. & Mag. N'at. Hist. (6) 

 vol. xviii. p. 4, pi. ii. figs. 1-13 ; also Fourteenth Rep. Fishery 

 Board for Scotland, pt. iii. p. 241, pi, ix. figs. 1-11. 



1902. Canthocanqytus JJuthiei, Lilljeborg, " Syuop, Spec, hueusque i7i 

 aquis dulcibus Suecise observ. Fam. Harpactic," K. Sv. Vet.-Akad, 

 Handlingar, Bd. xxxvi. no. 1, p. 41, pi. iii. figs. 5-10. 



Though the distribution of this species appears to be ex- 

 tensive, it has not been very frequently met with. It was 



14* 



