DIAPTOMUS. 219 



Genus 1 — Diaptomus. * 



MoNOCULUS, Linnceus, Fabricius, Jurine, 8fc. 

 Cyclops, Miillei', Lesmarest, Manuel, Sfc. 



Diaptomus, /. 0. Westwood, Partington's Cyclopfed. Nat. Hist., 

 art. Cyclops, 1S36 ; Entomologist's Text-Book, 1838. 

 Omethia, Templefon, Trans. Eut. Soc, ii, 118, 1S38. 

 Cyclopsina,! M. Echccirds, 1840. 



— Philiiypi, Wiegm. and Erichs. Archiv, 1813. 



— Baird, Zoologist, i, 56 ; Trans. Berw. Nat. Club, ii,154. 



— Dana, Proc. Amer. Acad. Sc, 1847. 



Character. — Head distinguisliable from body, though 

 firmly articulated with the first ring of thorax. Thorax 

 and abdomen, each of five segments. Antennules com- 

 posed of two branches. Foot-jaws not branched. Legs 

 five pairs ; the first pair having one branch of three arti- 

 culations, and the other of two ; the three succeeding 

 pairs having each a branch of three joints. External ovary 

 large, single, and lying across the abdomen. 



1. Diaptomus Castor. Tab. XXVI, figs. 1, 2, %a-j. 



MoNOCTTLTJs Castok, Jurine, Hist. Nat. Monoc, 50-73, t. 4-6, 1820. 

 Cyclops Castor, Desmarest, Cons, gen., 363, t. 53, f. 5, 1825. 



— Baird, Mag. Zool. and Bot., 324, t. 10, f. 1-8. 

 Cyclops c^ruleus, Miiller, Zool. Dan. Prod., No. 2411, 1776 ; 



Entomost., 102, t. 15, f. 1-9. 



— Latreille, Hist. Nat. Crust., iv, 265. 



— Bosc, Man. Hist. Nat. Crust., ii, 257. 

 MoNocuLUS c^RULEUS, Fabricius, System. Entomolog., 295. 



— Manuel, Euc. mcth., t. 264, f. 1-9. 



— Qmelin, Linn. Syst. Nat., 2997, No. 12, 



edit. 13th. 



* Erom ^i«, through ; and nrrajiai, to fly. 



f Though the genus Ci/clopsina has been adopted from M. Edwards by 

 PhUippi, and heretofore by myself, yet as its fouuder includes other species 

 belonging to the family in it which, as I have shown above (p. 204), cannot 

 be received, and as Mr. Westwood, four years previous to the publication 

 of M. Edwards's work, distinctly defined the genus Diaptomus, I now, obeying 

 the law of priority, assume his name ; and, indeed, while Mr. Westwood's 

 paper in which he founded the genus was still in MS. I had already indicated 

 his name for it in the 'Trans. Bcrw. Nat. Club' for 1835. 



