250 Dr. Max Weber on the 



the sea into the rivers and lakes. For since each species of 

 Bopyrus is attached to a distinct species of Palcemon, with a 

 regularity which, according to Giard, is characteristic of the 

 Epicaridge in general, we cannot suppose that the progeny of 

 a Bopyrid whose host was a Palcemon which perhaps fre- 

 quented the vicinity of the mouth of a river, made their way 

 into a genuine y'w ex -Palcemon. The truth must rather be 

 that Bopyrus has immigrated with Palcemon, and that the 

 subsequent development of species of the latter has been 

 accompanied by a parallel development of species among the 

 Bopyrida?. 



The Isopod freshwater fauna in the Indian Archipelago 

 consequently differs altogether from that of Europe, and con- 

 sists exclusively of marine forms, although the precise method 

 of their immigration from the sea is not directly obvious. 



Of the order Amphipoda our list includes only the genus 

 Orchestia, with four species. There appears to be a lack of 

 statements as to the occurrence of Amphipoda in the fresh 

 water of the Indian Archipelago, which is probably in itself 

 a proof of their rarity. Moreover it was only in four 

 localities, widely distant one from another, that I succeeded 

 in discovering the species which are described below. 



To reflect, however, that the fauna of the Indian islands 

 has been augmented by a few new members is to regard these 

 four new species of Orchestia from the less interesting point 

 of view. The following considerations are of greater im- 

 portance. 



Orchestia for esiana was taken by me near Maumeri, on the 

 north coast of East Flores, in and under fallen leaves at the 

 edge of a pool of fresh water, which lay in a small copse at a 

 distance of about 100 metres from the beach. 



On the south coast of the same island I found in the neigh- 

 bourhood of the village of Leila, in the small stream of the 

 same name, a few hundred metres distant from its mouth and 

 in perfectly fresh water, Orchestia Martensii under stones, 

 some in the stream itself, others on the bank. Both species 

 have consequently become adapted to fresh water and at the 

 same time to a mode of life that is to a certain extent amphi- 

 bious, since they also exist outside the water, beneath damp 

 leaves and stones. 



Similar to this was the mode of life of Orchestia montana } 

 which I met with near Loka at an altitude of 1150 metres, 

 in the highlands near Bonthain (Celebes) , in direct proximity 

 to a mountain-stream. 



Finally, I captured the fourth species, Orchestia parvi- 

 spinosa, beneath the trunk of a fallen tree and under stones 



