212 BRITISH ENTOMOSTRACA. 



into eight very short articulations, having between the 

 fourth and fifth a very small lateral joint, as in most of the 

 other species. Each articulation sends off one or more 

 setae. The antennules are similar to these organs in the 

 other species, as are also the posterior foot-jaws, which 

 consist of two rounded joints, terminated by a slightly- 

 curved hook. 



The first pair of feet does not differ in structure from the 

 others, and consists of two stalks, of nearly equal length, 

 each composed of three articulations, and each articulation 

 giving off two or three setae. The outer branch is more 

 slender than the inner. The fulcra or supports consist of 

 a broad, flat plate, wdth several tolerably long setae, as in 

 the preceding species. 



/^^^^;._Berwick Bay, 1835. Dover, North Foreland, 

 September 1849. 



Gemis 3 — Arpacticus.* 



Cyclops, Midler, Tilesitts, Baird, ^r. 

 MoNOCULUS, Mamtel, Gmelin, 8j'c. 

 Akpacticus, M. Edwards, Baird, Dana (iu part). 

 Nauplitjs {pars), Pfnlij^pi. 



Character. — Foot-jaws forming strong cheliform hands. 

 Antennules simple. Ovary single. 



1 . Arpacticus chelifer. Tab. XXIX, figs. 2, 3, 3 a-^. 



Cyclops chelifeb, Mi'dler, Zool. Dan. Prod., No. 2413, 1776; 

 Entomost., 114, t. 19, f. 1-3. 



— Latreille, Hist. Nat. Crust., iv, 269. 



— Bosc, Man. Hist. Nat. Crust., ii, 259. 



— Baird, Mag. Zool. and Bot., i, 328, t. 9, f. 15-22. 

 MoNOCTJLTTS CHELIFER, Manvel, Euc. meth., vii, 721, t. 264, f. 32-34. 



~ Gmelin, Linn. Syst. Nat., edit. 13th, i, 2998, 



No. 21. 

 Cyclops Johnstoni, Baird, Trans. Berw. Nat. Club, i. 97, t. 2, f. 4, 1 835 . 

 Cyclops armatus, Tilesius, Mem. Acad. Imp. St. Petersb., v, 366, 



t. 8, f. 7, 8. 

 AnPACTictis CHELIFER, Baird, Trans. Berw. Nat. Club, ii, 154, 1845. 

 Nauplius CHELIFER, F//ilipjn,Wicgm. and Erichs.Arcliiv, 1843, p. 69. 



* Erom apira^, rapacious. 



