a 
May 23, 1884. ] SCIENCE. 621] 
greatly increased of late. Probably other 
families require to be differentiated for certain 
that (Introduction, p. 804), ‘‘ as far as the ob- 
servations go at present, no distinct bathymet- 
Linh ih 
TM 
—— 
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MACRURUS AUSTRALIS. 
peculiar forms; and, of course, numerous fam- 
ilies, known from littoral fishes, have deep-sea 
representatives. It is obvious, then, that we 
rical regions which would be characterized by 
peculiar forms can be defined,’’ and that, *¢if 
the vertical range of deep-sea fishes is actually 
have, in such an aggre- 
gate, a combination of 
forms very different 
from any of the super- 
ficial faunas we have 
heretofore considered. 
We will be justified, 
therefore, in recogniz- 
ing for them a special 
realm, which has been 
called ‘Bassalia’ or 
the ‘ Bassalian realm.’ 
But caution is timely 
that it seems to be 
rather a heterogeneous 
one, and may hereaf- 
ter require restriction. 
The data now available 
are insufficient, how- 
ever, for differentiating 
what are, doubtless, 
the several constitu- 
ents or regions of this 
realm. 
Dr. Gunther has even expressed the opinion, 
saurididae, Alepocephalidae, Bathylagidae, Halosauridae, 
Bathythrissidae, Regalecidae, Trachy pteridae, Lophotidae, 
Chiasmodontidae, Stephanoberycidae, Berycidae, Grammicolepi- 
didae, Polymixiidae, Lycodidae, Brotulidae, Macruridae, and 
Ceratiidae, 
MELANOCETUS JOHNSONI. 
as it appears from the 
Challenger lists, then 
there is no more dis- 
tinct vertical than hori- 
zontal distribution of 
deep-sea fishes’? (op. 
cit., p. 305). There 
are reasons for beliey- 
ing that these generali- 
zations are at least ex- 
aggerated ; but it may 
be well to await the col- 
lection of more mate- 
rial, and the collation 
of more extensive data, 
before reversing them. 
Four factors must de- 
termine the bathymet- 
rical distribution of 
fishes: (1) tempera- 
ture, (2) the decrease 
and final absence of 
light, (3) the concomi- 
tant paucity or absence 
of vegetation, and (4) the pressure of the 
water. The relative importance of these sey- 
eral factors still remains to be studied, and 
their results discriminated. The absence of 
vegetable life confines the animal life to car- 
