When we turn to the Mysidacea the aspect is totally different. A minor part of the 

 genera or species of this order are true oceanic forms living either not far from the surface 

 (a few species of the Siriellinae) or in deeper strata {Gnathophausia, Eticopia, etc.). The large 

 majority of forms live more or less pelagically and frequently a little above the bottom either 

 near the coast in shallow water or somewhat longer from land down to some hundred metres. 

 But a large number of the "Siboga" stations are from near land to scarcely a score of miles 

 from the coa.st of one of the numerous islands in the Indian Archipelago, and consequently 

 well adapted for many types of Mysidacea. And the number of species of this order captured 

 by the "Siboga" is 47, 44 of which are described or enumerated here, while 3 are omitted, 

 each of these being represented by a single mutilated specimen too bad for a sufficient description. 

 But putting aside these 3 forms, the number 44 is somewhat higher than the sum of Mysidacea 

 hitherto known from the entire tropical belt around our globe. Among these 44 species only 

 10 can be referred with certainty to previously established forms, i species is somewhat uncertain 

 and at least 33, probably 34 are hitherto unknown forms. It may be pointed out that in no 

 earlier paper dealing with this order so many new species have been established. It was necessary 

 to erect 8 new genera, but only one of these shows a feature of more general interest, viz. 

 Lycomysis n. gen., in which the second joint of the mandibular palps is shaped as a strong, 

 excellent saw, certainly in order to take an active part in the treatment of the food. 



That the capture of 44 species of Mysidacea is an excellent result goes without mention. 

 But it is easy to prove that several forms still undiscovered live in the seas and straits traversed 

 by the "Siboga". Among the 34 (33) new species 17 are known from only a single station, 

 and among these 8 are represented only by a single specimen. And every Zoologist experienced 

 in questions on occurrence and distribution will admit that when three-fourths of a very 

 considerable number of species captured within a vast area are new to science and half of 

 these new forms have been found only at a single station, a good number of forms are still 

 discoverable. 



For various reasons I have not attempted to put together a view of the fauna of the 

 seas south of Asia. Our knowledge before 1905 of the Schizopoda from these seas was extremely 

 poor; in 1905 and later Illig published a number of forms in preliminary notes in the "Zoolog. 

 Anzeiger". In foot-notes I add descriptions of four new species of Mysidacea from various 

 places in the seas indicated and belonging to the Copenhagen Museum, as these species belong 

 to genera represented in the "Siboga" collection and it is possible to render them recognisable 

 without figures, but some other forms it was found necessary to omit. Even after the big 

 addition given in this volume our knowledge of the Euphausiacea inhabiting the tropical seas 

 south of Asia is somewhat imperfect, while of the Mysidacea it is probably — as far as I am 

 able to see — still very defective. 



