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Zoology. - "On the fresh-water fish+fauna of Neio Guinea". By 

 Prof. Max Weber. 



(Communicated in the meeting of November 24, 1906). 



In the year 1877 there appeared a "Quatrièine méraoire sur la 

 faune ichthyologique de la Nouvelle-Guinée", written by P. J. 

 Bleeker and containing 341 species. These species are exclusively 

 marine and brackish-water fishes and shew clearly, as might be 

 expected, that the littoral fish-fauna of New Guinea belongs to the 

 great Indo-Pacific fauna which extends from the East coast of Africa 

 to the islands of the Western Pacific. 



The same result is arrived at from the lists published by W. 

 Maci.eay in 187b and 1882, which treat of the iishes of the South 

 coast of New Guinea and Torres Straits. But none of these lists 

 accomplished what Blebker desired, namely, to give some insight 

 into the nature of the fresh-water fish-fauna of New Guinea. The 

 information which Bleeker desired was partly supplied by certain 

 communications, published by W. Macleay, E. P. Ramsay, .1. Dou- 

 glas Ogilby, A. Perugia and G. Boulenger, about fishes caught in 

 the Strickland, Goldie and Paumomu rivers, and in a number of 

 rivulets all situated in the south-eastern part of the island. The number 

 of fishes mentioned amount to about 30, but so long as the fish-fauna 

 of German and Dutch New Guinea remained unknown, it was 

 impossible to give a complete idea of the ichthyological fauna of this 

 big island. 



This was the more to be regretted inasmuch as fresh-water fishes 

 are of very great assistance in solving zoo-geographical problems. 

 In using them for this purpose we should however keep well in 

 mind the following points. 



If in regions, at present separated by the sea, identical or closely 

 allied fresh-water forms are found, to which the sea affords an insur- 

 mountable barrier, one may freely draw the conclusion that these 

 regions were formerly either directly or indirectly connected. Among 

 the fresh-water fishes there are however whole categories which 

 cannot be used as factors in such an argument or only with great 

 caution. These are the migratory fishes and those that can live also 

 in brackish water and indeed even in sea-water. 



The so-called law of E. von Martens states that from the Poles 

 to the Equator the number of brackish water animals increases. 

 This is also true for fishes and especially for those of the Indo- 

 Australian Archipelago, and in a very remarkable degree for those 

 of the islands east of Borneo and Java. The great Sunda Islands 



