THE BRANCHIOPODA 53 



SUB-CLASS BRANCHIOPODA. 

 ORDER 1. Anostraca. 



Carapace absent ; paired eyes pedunculate ; antennae prehensile in 

 male, reduced in female ; trunk-limbs, 11 or 19 pairs, none post-genital ; 

 furcal rami unsegmented ; development with metamorphosis. 



Family POLYARTEMIIDAK. Polyartemia, Fischer (Fig. 32). Family 

 BRAXCHIPODIDAE. Brancldpus, Schaffer ; Ghirocephalus, Prevost (Fig. 

 21); Artemia, Leach; Ifranchinecta, Verrill (Fig. 15). Family 

 THAMNOCEPHALIDAE. Thamnocephalus, Packard. 



ORDER 2. Notostraca. 



Carapace forming a dorsal shield ; paired eyes sessile ; antennae 

 vestigial ; trunk-limbs, 40 to 63 pairs, of which 29 to 52 are post-genital ; 

 furcal rami multiarticulate ; development with metamorphosis. 



Family APODIDAE. Apus, Latreille ; Lepidurus, Leach (Fig. 16). 



ORDER 3. Conchostraca. 



Carapace bivalved, enclosing head and body ; paired eyes sessile, 

 coalescent ; antennae biramous, natatory; trunk limbs, 10 to 27 pairs, 

 of which to 16 are post-genital ; furcal rami claw-like ; development 

 usually with metamorphosis. 



Family LIMNADIIDAE. Limnadia, Brongniart ; Estheria, Ritppel 

 (Fig. 17) ; Cyclestheria, G. O. Sars. Family LIMNETIDAE. Limnetis, Love'n. 



ORDER 4. Cladocera. 



Carapace bivalved, generally enclosing body but leaving head free, 

 sometimes reduced and serving only as a brood-sac ; paired eyes sessile, 

 coalesced ; antennae biramous (except in the female Holopedium), natatory ; 

 trunk-limbs, 4 to 6 pairs, none of which are post-genital ; furcal rami 

 claw-like ; development embryonic, rarely with metamorphosis. 



SUB-ORDER 1. CALYPTOMERA. 



Carapace completely enclosing body and limbs. 



Tribe 1. CTENOPODA. Six pairs of trunk -limbs all similar and 

 foliaceous. 



Family SIDIDAE. Sida, Straus ; Latona, Straus ; Penilia, Dana. 

 Family HOLOPEDIIDAE. Holopedium, Zaddach. 



Tribe 2. ANOMOPODA. Five or six pairs of trunk-limbs, first two 

 pairs more or less prehensile. 



Family DAPHNIIDAE. Daphnia, O. F. Miiller (Fig. 18); Moina, 

 Paird ; Simocephalus, Schodler (Simosa, Norman). Family BOSMINIDAE. 

 ttosmina, Baird. Family LYNCODAPHNIIDAE. Ilyocryptus, G. O. Sars ; 

 Macrothrix, Baird. Family LYXCEIDAE. Lynceus, 0. F. Mu'ller ; 

 Chydorus, Leach ; Eurycemis, Baird ; Pleuroxus, Baird (Fig. 26) ; 

 Monospilus, G. 0. Sars. 



