PART II 

 Family ALPHEIDAE 



It is especially to the important investigations of Professor Coutière that science is 

 indebted for the fact that our knowledge of the Family Alpheidae has increased to such a great 

 extent, not only as regards the morphology and the biology of these interesting animals, but 

 also in view of the considerable number of new genera, new species and new varieties with 

 which he has made us acquainted. Coutière also first called attention to the great importance 

 of the relative measurements of the thoracic appendages and of the telson as specific characters, 

 characters that previously had been overlooked by the carcinologists and it was just by means 

 of these new characters, that often specimens of small size of Alpheiis or Synalpheus proved 

 to belong to species that were still unknown, while formerly such specimens usually would be 

 regarded as juvenile forms or at most as varieties. 



At present not less than 19 genera are included in this family, one of which, however, 

 Racilius Paulson, is regarded by Coutière as doubtful, while the genus Parathanas Sp. Bate 

 has been created for specimens that apparently were still in a larval stage. The genus Aretopsis 

 is the only new one, discovered by this expedition. Excepting the old genus Alphcus and the 

 genus Synalpheus, that previously was united with the former, all these genera are represented 

 by few species and nine of them even by one species only. The genera Alpheus, Synalpheus, 

 Ogyris, Automate, Alphcopsis, Betacus, Joiisseaumea and Athanas are distributed not only 

 over the Indopacific region, but occur also in the Atlantic or on the coasts of America, the 

 Mediterranean or the Black Sea and Alpheopsis Haugi Cout. inhabits a freshwater lake of 

 the French Congo at 200 kil. from the sea. The other genera of this family are confined to 

 the Indopacific region. While all the first mentioned genera were collected by the "Siboga", 

 of the latter only Arete and Aretopsis have been observed. 



As regards the distribution of the other genera, we know that Athanopsis Cout., 

 Pterocaris Heller, Parabetaeus Cout., Amphibctacus Cout. and Raeilius Paulson have up to the 

 present time only been observed in the Red Sea or at Djibouti ; the remarkable genus Cheirothrix 

 that was discovered by the "Challenger", occurs at Cape York, the genus Alpheinus Borr. at 

 the Loyalty Islands and Metabetaeus, finally, is still only known from the island of Funafuti. 

 The three last named may perhaps once prove to exist also in the East Indian Archipelago, 

 like also the two species of Parathanas Sp. Bate, that occur at the Philippine Islands. 



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