392 Mr. W. F. de Vismes Kane on 
Barent’s Sea, Novaia Zemlya, Kara Sea, Finmarken, Klos- 
tereld Fiord (Norman), North Sea, Labrador, and the Atlantic 
coasts of North America, at depths varying from 23 to 235 
fathoms, but is absent from the Danish waters and the Ost 
See. Czerniavski also mentions its having been dredged in 
the White Sea on a muddy bottom at a depth of 64 fathoms. 
Mysis relicta, the freshwater species, the subject of this paper, 
has a very remarkable distribution. It would seem that its 
first discoverer was William Thompson, of Belfast, who in 
his ‘ Natural History of Ireland,’ published 1856, mentions 
that on July 12th, 1851, he examined the contents of the 
stomach of a Pollan (Coregonus pollan, Thompson) taken in 
Lough Neagh, Ireland, which “ proved to be wholly of the 
genus Mysis (not less than 100), except a Limneus pereger.”’ 
Unfortunately he did not enquire further into the species, and 
made no further reference toit. Just ten years later, in 1861, 
Professor Lovén published a paper on the Crustacea of Lakes 
Vettern and Venern, in Sweden, and announced the discovery 
of the following, namely: Mdysis relicta, Idvthea entomon, 
Linn., Pontoporeia affinis, Lindstrém, Gammarus loricatus, 
Sabine, and Gammarus cancelloides, Gerstfeldt; all of which 
were closely allied to, if not identical with, marine forms. 
In 1867 G. O. Sars announced its discovery in Lake Mjésen, 
in Norway also, and eight other Swedish lakes in addition to 
Lakes Vettern and Venern. Subsequently various lakes in 
Russia and Finland were added to the list of HKuropean 
habitats. Sars also records its having been taken in the 
brackish water of the northern part of the Gulf of Bothnia, 
but not south of Quarken. In North America, Drs. Hoy, 
Stimpson, and Smith found it in Lakes Michigan and Superior, 
between which and the sea there is no evidence of any con- 
nexion in recent geological times. Lake Ontario, however 
(from which M. relicta appears now absent), evidently formed 
once a part of the St. Lawrence Valley, and marine shells of 
the Quaternary deposit have been found there as far up as 
Kingston; so that it has been suggested that the river flowing 
out of Lake Superior might have anciently afforded an access 
for marine species thence. 
So far as to the published distribution of the species up to 
the present date. I have now to place on record further 
information as to its occurrence in Ireland, which marks at 
present the most southern range of its extension. In the 
autumn of 1898 the Rev. Canon Norman showed me a single 
specimen procured from Lough Neagh, which stands recorded 
in his monograph on British Myside. The history of the 
discovery is as follows. Not having been aware of Thomp- 
