I! 



\ REVISION 01 rin. KKiriMi sri-xiKs or 



(1891), when he found the filter-beds of tho marine baths at 

 Bootle — close to the first-mentioned locality — swarming with it. 



Genus ACARTIA, Dana. 

 1. Acartia longiremis, Lilljeborg (PI. XIV., figs. 1-4). 



185.'}. Dias longiremis, Lilljeborg (9), p. 181, pi. XXIV., 



figs, 1-13. 

 L868. ,, „ Claus (18), p. 193, pi. XX XI II., 



figs. 6-14. 

 1878. „ „ Brady (32), p. 51, pi. V. 



1881. ,, ,, Giesbreoht (37\ p. 140; idem (35), 



p. 3. 

 L881. ,, bijilosus, Giesbreoht (37), p. 147 ; idem (35), p. 3. 

 1881. ,, ? disemdatus, Gicsbrecht (37), p. 148; idem (35), 



p. 3. 

 1887. ,, ? „ I, C. Thompson (50b), p. 36, pi. V., 



figs. 1-6. 

 1890. ,, longiremis, Bourne (64), p. 147, pi. X [., figs. 4-6. 



It has been proposed bj r Dr. W. Gicsbrecht to break up the 

 forma hitherto considered as belonging to Dias longiremis, Lill- 

 jeborg, into two, or perhaps three, distinct species: — I), longiremis 

 (restricted form), D. bifilosus, Giesbreoht, and D. disoaudatus, 

 Giesbreoht. The last-named may or may not be considered as 

 having been previously included under the old term longiremis. 

 The characters relied upon by Giesbreoht to uphold this separa- 

 tion are as follows : — 





longiremis. 



bifilosus. 



discaudatus. 



Frontal filaments 



absent 



two 



absent 



Last thoracic seg- 



armed with two 



unarmed 



unarmed 



ment 



large&seT era! 

 smaller spines 







Furoa 



long 



shorl 



short and (in the 

 female) dilated 









Fifth pair of feel 



small 



large 



very large 



(male) 









Fifth pair of feet 



large 



small 



\ erv small 



(female) 









To me it appears that these characters — trivial even when 

 displayed to the best advantage on paper— are of even less ac- 

 count when put to a practical tost , their inconstancy even more 

 than their intrinsic triviality being fatal to their acceptance as 



109 



