690 MR. H. G. JACKSON ON THE 



C Postero-lateral processes of telson produced to sharp points 14. 



13.] 



(. Postero-lateral processes of telson obsolete, or small and blunt . 15. 



f Antennae as long as or longer than thorax, setose. 

 14. ^ novcB-zealandicB (New Zealand, Chile). 

 (. Antennae sliorter than thorax, not setose oceanica (Europe). 



("Eyes large and separated by less than their horizontal length... 16. 

 (.Eyes small and separated by more than their horizontal length. 17. 



JFlagellum of antenna with about 20 long and slender joints. 

 rioJiardsoiics (Colombia — terrestrial). 

 Flagellum of antenna with about 17 short and setose joints. 

 glahrata (Cape). 



/■Flagellum of antenna with about 20 joints ... italica (Mediterranean). 



1 Flagellum of antenna with about 16 joints ... simoni (Venezuela — ■ 



(. terrestrial). 



(7) TAe g'e?^^6S Ligia, Fabricius, 1798. 

 I quote Sars's diagnosis of the genus : — 



" Body regularly oval, or oblong oval, moderately convex 

 above, with the metasome not abruptly contracted ; last 

 segment rather broad, with distinct epimeral plates. Eyes 

 large and convex. Antennulae very small, with the last 

 joint rudimentary, nodiform. Antennse rather strong and 

 elongated. Mandibles with a ciliated lappet and numerous 

 penicils behind the cutting-part. Maxillipeds comparatively 

 short and stout, with the terminal part rather expanded, 

 epignath rounded. Legs gradually increasing in length 

 posteriorly, dactylus distinctly bi-unguiculate. Opercular 

 plate of pleopoda sub-branchial. Uropoda more or less 

 elongated, basal part not produced inside ; rami narrow, 

 styliform, subequal, each with a single apical spine," 



The only point that will not hold for the whole genus is that 

 relating to the contraction of the metasome. It may or may not 

 be as broad as the mesosome. 



I have thought it desirable to include in the following 

 descriptions, for the sake of uniformity, complete accounts of all 

 species that I have examined, although three of them have been 

 fully described elsewhere. When full synonymy and figures have 

 already been published, I have been content to refer to them when 

 I have been satisfied as to their correctness. 



The order in which the characters of each species are dealt with 

 is based on convenience in examination, and does not pretend to 

 any natural or logical order. Although the males and females of 

 a species may difi^er considerably, I have considered it safe to 

 re-describe Some species, and describe a new species from the female 

 only, as, with the, data given above, it may be predicted with some 

 certainty in what characters the male may be expected to difier 

 from the female, and to found the specific diagnosis on common 

 characters. 



