Long-legged  Sac  Spiders  and  Allies  -  Family:  Cheiracanthiidae
      Only 12 of 366 species from the Family: Cheiracanthiidae occur in Australia and of those only two may be encountered in the Northern Rivers.   Many of the Sac Spiders are medium sized with a rather elongated cephalothorax and abdomen.   Their jaws are often very large, sometimes as long as the cephalothorax. The first pair of legs are usually quite a bit longer than the others. 
      The Cheiracanthiidae were given their name by the Russian Wladimir A. Wagner in 1887.   Wagner was a psychologist with a special interest in comparative and evolutionary psychology.   He did however also study spiders and obtained a doctorate in zoology.  He is credited with being the first to suggest that the shape and construction of the male genitalia in spiders be used to group the species into higher taxons.
​      Wagner wrote a lengthy argument on the subject in the 'Proceedings of the Russian Entomological Society' as he was quite dissatisfied with the prevailing practice at the time to distinguish between species merely by real life observations of body parts that could well have considerable variation between individuals of the same species.  And, therefore of course,  lead to frequent misidentification of specimens.   To strengthen his argument he provided numerous illustrations as well.
      Slender Sac Spider  -  Cheiracanthium gracile

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      Biting Sac Spider  -  Eutittha mordax

Taxonomy:
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Phylum:   Arthropoda   (Arthropods)
          > Subphylum:   Chelicerata   (Chelicerates)
                    > Class:   Arachnida   (Arachnids) 
                                        > Order:   Aranea   (Spiders)
                                                  > Suborder:   Araneomorphae   (Typical Spiders)
                                                            > Infraorder:   Entelegynea   (Entelegyne Spiders)
                                                                      > Superfamily:   Corinnoidea   (Corinnoid Spiders)
                                                                                > Family:   Cheiracanthiidae   (Long-legged Sac Spiders and Allies)
 ​                                                                                                           > Genus:   Cheiracanthium   (Long-legged Sac Spiders)
                                                                                                                      > Species:  C. gracile  -  Slender Sac Spider
 ​                                                                                                           > Genus:   Eutittha
                                                                                                                      > Species:   E. mordax  -  Biting Sac Spider

References  and  links:
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>      Mikhailov, K.G.,    (2004).   'A brief historical overview of the development of arachnology in Russia.'  in:   Logunov, D.V. and  Penney, J., (eds.). 'European Arachnology.'    Arthropoda Selecta. Spec. Issue. No. 1. P. 21-34.. European Arachnology 2003. 21-34. 
>      Wagner, W.A.,  (1887).   'Copulationsorgane des Männchens als Criterium für die Systematik der Spinnen.'   Horae Societatis Entomologicae Rossicae 22: 3-132.
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       https://wsc.nmbe.ch/genlist/113/Cheiracanthiidae

Photographic   contributions:

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