90 
Sitzungsberichte: Faunistische Sektion. 
Aus dem Vorstehenden ersieht man, daß viele Hände sich regen, um die bisher 
ertragiosen Flächen des Großen Moosbruchs zu kultivieren und für die Menschheit 
nutzbar zu machen, daß von Jahr zu Jahr die ertraglose Fläche kleiner wird, bis 
schließlich dieses nach vielen Richtungen so eigenartige und interessante Gebiet in 
seiner Urwüchsigkeit verschwunden sein wird. 
5. Die weitere Diskussion über die Erforschung der ostpreußischen Moore wurde 
auf die nächste Sitzung vertagt. 
Sitzung am 20. Februar 1913 
im Zoologischen Museum. 
1. Der Vorsitzende der Sektion, Herr Prof. Lühe, legt unter gleichzeitiger 
Demonstration einschlägiger Objekte aus dem Zoologischen Museum ein Manuskript vor: 
On a collection of Gammarus from the Königsberg Museum 
by Mrs. E. W. Sexton, 
Marine Biological Laboratory, Plymouth 
(with plate IV.) 
I am greatly indebted to Prof. Dr. Lühe for the opportunity of examining an 
interesting collection of Gammarus preserved in the Königsberg Museum. 
There are three species of Gammarus represented, viz., the purely freshwater 
species G. pulex Lnsnsr. ; the brackish water G. zaddachi Sexton, which occurs most 
frequently in the brackish water of estuaries and harbours, but can also flourish 
in fresh water; and 6r. locusta Lnsrx., which, though hitherto considered a purely 
marine species, can also live and breed in brackish water, as is shown in this collection. 
Ali three species are fouud in the neighbourhood of Königsberg, and specimens can 
be seen in the Museum in the excellent series of dredgings preserved there, taken 
from Memel on the one side to the Putziger Wiek on the other. Besides this series, 
there are specimens of G. pulex, G. locusta and G. zaddachi from the Crimea, and 
of G. zaddachi from Norway, taken by Rathke; some G. zaddachi from Kiel, by 
Möbius; and some G. pulex from the Geserich-See, by Zadd^ch. 
The contents of the tubes and their original labels are given in detail below. 
It will be noticed that most of the specimens are G. zaddachi though labelled 
G. locusta, the confusion between the species being principally due to the incom- 
pleteness and indefiniteness of the original description of G. locusta, and to the lack 
of illustrative figures. There is undoubtedly a very great resemblance between 
G . locusta and G. zaddachi especially in the younger stages of development, but the 
characters which distinguish them are definite and constant. 
G. zaddachi has only recently been established as a separate species (Proc. 
Zool. Soc. London, Sept. 1912, p. 657) although described as long ago as 1844 by 
Zaddach in his ”Synopseos crustaceorum Prussicorum prodrom us*‘. He attributed 
it, however, to G. locusta as described by Milne Edwards, his specimens agreeing 
fairly well with this description except in the two points particularly noted, viz., the 
clusters of long hairs on both the antennae, and the proportions of the rami of the 
3 rd uropods. But he was evidently doubtful of the Identification of the two species, 
for he added ”si igitur illa descriptio accurata esset, nova generis Gammari species ani- 
malibus hic descriptis constitueretur“. In recording the species again in 1878 in ”Die 
Meeres-Fauna an der preußischen Küste u , he again referred to these distinctions and 
gave a detailed account and figures of the male, the female, and the young. 
