220 THE CRUSTACEA 



Alcirona, Hansen ; Tacliaea, Schiodte and Meinert. Sub-Family ARGA- 

 THONINAE. Argathona, Stebbing. Sub-Family BARYBROTINAE. Barybrotes, 

 Schiodte and Meinert. Sub -Family AEGIXAE. Aega, Leach ; Rocinela, 

 Leach. Sub -Family CYMOTHOIXAE. Cymothoa, Fabricius ; Geratothoa, 

 Dana ; Meinertia, Stebbing ; Nerocila, Leach. Family SEROLIDAE. 

 Serolis, Leach. Family SPHAEROMIDAE. Sub-Family LIMXORIINAE. 

 Limnoria, Leach. Sub-Family SPHAEROMIXAE. Sphaeroma, Latreille ; 

 Oymodoce, Leach ; Dynametw, Leach ; Campecopea, Leach ; Monolistra, 

 Gerstaecker ; Vireia, Dollfus ; Cassidina, H. Milne-Edwards ; Ancinus, 

 H. Milne -Ed wards. Sub- Family PLAKARTHRIINAE. Plakarthrium, 

 Chilton. 



SOB-ORDER 4. Valvifera, G. O. Sars (1882). 



Abdominal somites more or less coalesced ; antennal peduncle of live 

 segments ; mouth-parts normal ; coxopodites of thoracic legs expanded 

 into coxal plates, rarely quite concealed -beneath pleural plates ; first pair 

 of pleopods similar in the two sexes (except in Pseudidothea), second pair 

 present in female ; uropods lateral, opercular, folded inwards over pleo- 

 pods, exopodite vestigial or absent. 



Family IDOTEIDAE. Idotea, Fabricius ; Chiridotea, Harger ; Glyptonotus, 

 Eights. Family CHAETILIIDAE. Chaetilia, Dana. Family PSEUDIDO- 

 THEIDAE. Pseudidothea, Ohlin. Family HOLOGXATHIDAE. Holognathus, 

 G. M. Thomson. Family AMESOPODIDAE. Amesopous, Stebbing. Family 

 ARCTURIDAE (ASTACILLIDAE). Arcturus., Latreille ; Astacilla, Cordiner ; 

 Anarcturus, zur Strassen. 



SUB-ORDER 5. Oniscoidea, G. 0. Sars (1882). 



Abdominal somites rarely coalesced ; antennules minute ; antennal 

 peduncle of five segments ; mouth-parts not suctorial, mandibles without 

 palp, maxillae reduced ; coxopodites of thoracic legs expanded into coxal 

 plates, usually completely coalesced with body, rarely defined by sutures ; 

 first pair of pleopods usually differing in the two sexes, sometimes absent, 

 second pair present in female ; uropods sub-terminal, generally biramous and 

 styliform ; terrestrial in habits, often with pseudo- tracheae in pleopods. 



Family LIGIIDAE. Ligia, Fabricius ; Ligidium, Brandt. Family 

 TRICHONISCIDAE. Trichoniscus, Brandt ; Haplophthalmus, Schiodte. Family 

 TYLIDAE. Tylos, Audouin ; Helleria, von Ebner. Family . ONISCIDAE. 

 Sub-Family SCYPHACIXAE. Scyphax, Dana. Sub -Family ONISCINAE. 

 Oniscus, Linnaeus ; Porcellio, Latreille (Fig. 118). Sub-Family ARSIADIL- 

 LIDIXAE. Armadillidium, Brandt; Gnbaris, Brandt ( Armadillo, 

 Latreille). 



SUB-ORDER 6. Epicaridea, Latreille (1831). 



Parasitic forms in which the adult females are greatly modified, often 

 asymmetrical, sometimes without appendages and without segmentation of 

 the body ; mouth-parts suctorial, with simple piercing mandibles, max- 

 illulae and maxillae vestigial or absent ; pleopods, when present, without 

 sexual modification ; uropods uniramous, very small, often absent ; late 



