THE CRUSTACEA 



Alcirona, Hansen ; Tachaea, SchiiJdle and Meinert. Sub-Family Arga- 

 THONiNAE. Argathona, Stelibing. Sub-Family Barybrotinae. Bartjbrotes, 

 Schicidte and Meinert. Sub -Family Aeginae. Aega, Leach ; Rocinela, 

 Leach. Sub -Family Cymothoinae. Gymothoa, Fabricius ; Geratothoa, 

 Dana ; Memertia, Stebbing ; Nerocila, Leach. Family Serolidae. 

 Serolis, Leach. Family Sphaeromidae. Sub-Family Limnoriinae. 

 Limnoria, Leach. Sub-Family Sphaerominae. Sfhaeroma, Latreille ; 

 Gymodoce, Leach ; Dynamene, Leach ; Gampecopea, Leach ; Monolistra, 

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

 H. Milne -Edwards. Sub- Family Plakarthriinae. Plakarfhriuvi, 

 Chilton. 



Sub-Order 4. Valvifera, G. 0. Sars (1882). 



Abdominal somites more or less coalesced ; antennal peduncle of five 

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

 into coxal plates, rarely quite concealed beneath jjleural 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 ; Ghiridotea, Harger ; Glyptonotus, 

 Eights. Family Chaetiliidae. Ghaetilia, Dana. Family Pseudido- 

 theidae. Pseudidothea, Ohlin. Family Holognathidae. Holognathus, 

 G. M. Thomson. Family Amesopodidae. Amesopious, Stebbing. Family 

 Arcturidae (Astacillidae). Arcturas, 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 comjaletely coalesced with body, rarely defined by sutures ; 

 first pair of pleopods usually difl'ering in the two sexes, sometimes absent, 

 second pair present in female ; uroiJods sub-terminal, generallj^biramous and 

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



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

 Trichoniscidae. Trichonisc us, Br Audt; Haplophthalmus, Schiodte. Family 

 Tylidae. Tylos, Audouin ; Helleria, von Elmer. Family Oniscidae. 

 Sub-Family Scyphacinae. Scyphax, Dana. Sub -Family Oniscinae. 

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

 lidinae. Armadillidium, Brandt; Gubaris, Brandt {= Armadillo, 

 Latreille). 



Sub-Order 6. Epicaridea, Latreille (1831). 



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

 asymmetrical, sometimes without aj^pendages 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 



