Luminous Organs of Fish — HANEDA 
221 
amiried microscopically a large number of 
bacteria and some duct cell fragments could 
be seen. In the latter could be seen what 
were apparently bacteria since they stained 
well with ZiehFs solution and were Gram 
negative. Bacteria which had been taken 
from the luminous gland and cultured in 
media were tested for luminescence in the 
same solution as were the emulsions. 
One hundred different strains of the lumi- 
nous bacteria were obtained by the usual bac- 
teriological techniques from 100 of each of 
the two different types of Acropoma japoni- 
cum. The cultures of bacteria taken from 
each of the. types of fish showed some differ- 
ences. On the basis of preliminary tests it 
appears that they represent two heretofore 
unknown species of bacteria which will be 
discussed at length in a separate paper. I 
tested the agglutination reactions of repre- 
sentative strains of these two new kinds of 
bacteria, and they showed a strain specificity 
similar to that of other symbiotic luminous 
bacteria (Kishitani 1930, 1932; Yasaki and 
Haneda, 1936). 
LUMINESCENCE IN THE FAMILY 
LEIOGNATHIDAE 
Material 
The fishes belonging to the family Leiog- 
nathidae are true shallow-water forms, and 
are abundant in the southern Sea of Japan 
and in tropical seas. When I published my 
account of the luminescence of these fishes 
in 1940 I was not aware that their lumines- 
cence was already known, and it was only by 
chance that I found, in 1943, a reference to 
the work of J. W. Harmes in Biological 
Abstracts in the Raffles Museum Library. It 
is an abstract of a paper which appeared in 
1928 ,. entitled "Bau und Entwicklung eines 
eigenartigen Leuchtorganen bei Equula spec.” 
Unfortunately I have not yet been able to 
see the full account of this discovery. How- 
ever, while working independently on lumi- 
nous organisms of the South Sea Islands at 
the Palao Tropical Biological Station, I dis- 
covered that Gazza minuta and several other 
species in this family are also luminescent 
when alive. The Leiognathidae living in shal- 
low waters are not provided with externally 
visible luminous organs and superficially they 
resemble ordinary non-luminous fishes. For 
this reason their luminosity was unexpected. 
Besides Gazza minuta I collected 15 other 
species of the Leiognathidae. Investigation of 
these species reveals that they all possess a 
luminous organ of a type similar to that of 
Gazza minuta . 
Since the luminescence of these fishes of 
the family Leiognathidae was, I thought, un- 
known, I published the results of my investi- 
gations in 1940. I now present the results 
in revised form. 
Gazza minuta occurs in clear water in 
Palao at a depth of about 30 meters and 
Leiognathus equulus lives in turbid water in 
the vicinity of mangrove trees at a depth of 
1-2 meters. In Palao and Yap, L. equulus 
ranged in length from 60 to 70 mm.; in Po- 
nape it was 180 mm. long; and in Sandakan, 
200 mm. long. In Sandakan, the Chinese 
fishermen catch these fishes in nets and bring 
them every morning for sale in the Sandakan 
fish market. 
In Japan there are three species, L. argen- 
teum (Japanese name Uchi-Hiiragi ) , L. rivu- 
latum (Oki-Hiiragi), and L. elongatus (Hime- 
Hiiragi ) . 
L. argenteum and L. rivulatum are com- 
mon on the southern coast of Japan. They 
are extremely abundant in Nagasaki where 
they are called Gira-gira or Gira. In Kochi 
they are called Nirogi. In the bay of Urado 
near the city of Kochi many old men may 
be seen fishing for Nirogi on any fine autumn 
day. L. argenteum is caught almost entirely 
by hook and line. This species lives in rather 
turbid water along the shores of the river 
estuaries, and it is from this fact that the 
