PISCES. 
179 
species is represented as a variety by this author, who does not 
hesitate, as we shall see, to use binominal nomenclature for these 
varieties. It is to be regretted that no serviceable descriptions 
are added, so that the species of that country remain in the 
same obscurity as before. He distinguishes 
1. Trutta salar with two varieties : 
a. The migratory form, ascending the rivers from the Gulfs 
of Bothnia and Finland, as well as from the White Sea. 
b. A large lacustrine Salmonoid of Lake Ladoga had been 
compared with one of the Salmonoids of Lake Wener {Salmo 
salar, var. lacustris, Hardin) by Mag. Widegren, who declared 
them to be identieal, and of the same species as the common 
Salmon. Hr. Malmgren agrees with him, inasmuch as he eon- 
siders both to be the deseendants of the Salmon of some former 
period; specimens of this Salmon remained in those lakes when 
they became separated from the sea ; and the raee of these indi- 
viduals thus shut up from the sea underwent certain changes 
in the course of thousands of years, which ought not to be 
overlooked, and which induce the author to propose for this 
variety of Trutta salar the name of Trutta relicta. — The 
characters by which this ‘^Waricty^^ is distinguished by Dr. 
Malmgren are of too trivial a nature to deserve space in this 
Record, except one, viz. that the ova of Trutta relicta are con- 
siderably smaller than those of the Salmon. 
2. Trutta trutta with three varieties. 
a. The migratory form {S. trutta, auct.) . 
h. Trutta lacustris, with S. ferow, S. microps, &c. as syno- 
nyms. Differences in the size of the scales and of the teeth are 
of no value ; the former vary much in different individuals, and 
the size of the teeth depends entirely on the particular food taken 
by the fish. 
c. Trutta fario. Large examples and, again, young ones of 
the common Trout cannot be distinguished from specimens of 
the Sea-Trout of the same size; therefore the two speeies can- 
not be seriously maintained. 
We might have been satisfied with giving a simple record of 
these novel views, if they had been written for ichthyologists 
only, who would at once perceive the fallaciousness of conclusions 
based upon facts which (as regards the Salmonoids mentioned) 
have evidently not been thoroughly examined, not perfectly un- 
derstood, and which at all events have not been proved. But 
as they will be read by men less conversant with ichthyology, 
who may perhaps make use of them for their own special study, 
we cannot allow them to pass without comment. 
According to Hr. Malmgren, the criterion of species would be 
the unity of characters as they appeared in a group of individuals 
living at a remote period, say in the Glacial period; not all 
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