378 
PACIFIC SCIENCE, Vol, V, October, 1951 
sion of these bacteria will be presented in a 
separate paper. 
SUMMARY 
Some of the fishes belonging to the families 
Gadidae and Macrouridae are luminous and 
possess the "open type” of luminous organ 
containing luminous symbiotic bacteria. It 
consists of a gland in the ventral muscles lying 
in a scaleless depression between the pelvic 
fins. This is a characteristic of these fishes. 
Their luminescence is controlled by means of 
chromatophores. Normally they are deep-sea 
fishes although at times some of the Gadidae 
may be caught in shallow water. Observations 
were made on 14 species of the Macrouridae 
and 2 species of the Gadidae. Their luminous 
ducts are very similar but vary in size. In some 
species they are very long, in others very 
short, and in others extremely small and not 
visible from the outside. Some of the lumin- 
ous ducts are of a comparatively simple con- 
struction while others are extremely complex. 
I consider the luminous symbiotic bacteria 
which were cultured from these many fishes 
to be a species of the new group of luminous 
bacteria, but a more complete discussion will 
be presented later in a separate paper. 
REFERENCES 
Franz, V. 1910. Die japanischen Knochen- 
fische der Sammlungen Haberer und Do- 
flein. Abhandl. Wiss. 11 kl. Sitzher. 4: 28. 
Hickling, C. F. 1925. A new type of lumi- 
nescence in fishes. Jour. Mar. Biol. Assoc. 
{U. K.) (n. s.) 13(4): 914-929. 
1926. A new type of luminescence in 
fishes. Jour. Mar. Biol. Assoc. (U. K.) (n. s.) 
14: 495-506. 
1931. A new type of luminescence in 
fishes, III. The gland in Coelorhynchus 
coelorhynchus Risso, Jour. Mar. Biol. Assoc. 
{Plymouth) 17: 853-875. 
Haneda, Y. 1938. Ueber den Leuchtfisch, 
Malacocephalus laevis (Lowe). Jap. Jour. 
Med. Sci. 111. Biophysics Trans, and Ahs. 
5(3): 355-366. 
Imai, H. 1942. Studies on luminous symbiotic 
bacteria. Seiikai Zasshi 61(4): 454-467. (In- 
Japanese.) 
Kishitani, T. 1930. Studien fiber die Leucht- 
symbiose in Physiculus japonicus Hilgendorf, 
mit der Beilage der zwei neuen Arten der 
Leuchtbakterien. Tohoku Imp. Univ. Sci. 
Rpts., 4 Series, Biol. 5(4): 801-823. 
1932. Studien fiber Leuchtsymbiose 
von japanischen Sepien. Folia Anatomica 
Japonica 10(3): 315-413. 
Meissner, G. 1926. Bakteriologische Unter- 
suchungen fiber die symbiontischen Leucht- 
bakterien von Sepien aus dem Golf von 
Neapel. Zenthl. f. Bakt., Abt. II. 67(8): 
194-238. 
Parr, A. E. 1946. The Macrouridae of the 
Western North Atlantic and Central America 
Bingham Oceanogr. Coll. Bui. 10: 1 - 
99. 
ViNCiGUERRA, D. 1932. Del genere Hymeno- 
cephalus (H. italicus, Gigl.) Ann. Mus. Civ. 
di Storia Nat. Genova, Estratto 56: 1-13. 
Yasaki, Y. 1928. On the nature of the 
luminescence of the knightfish {Momcen- 
tris japonicus (Houttuyn)). Expt. Zool. 
50(3): 495-502. 
and Y. Haneda. 1935. On the lumi- 
nescence of the deep sea fishes, family 
Macrouridae. Ohyo Dobutsugaku Zasshi [jour. 
Appl. Zool] 7(4): 165-176. (In Japanese.) 
