374 LUMINOUS ORGANISMS OF FAR EAST 



a supposedly parasitic male, of the deep sea angler fish Crytosparus 

 couesi, from the Pacific coast of northern Japan which is supposed to 

 be luminous. 



The structure of the light organs and the observation of luminous 

 phenomena of self-luminous fish have been investigated by Ohshima 

 (1911). He studied two species of deep sea luminous shark and some 

 specimens of the Myctophidae and Sternoptychidae. In my observa- 

 tion ( 1950 ) on living material of Yarrella and Pohjipmis from Suruga 

 Bay, I recognized a peculiar color filter, hitherto considered a lens, 

 situated between the luminous tissue and the lens. Recently I ob- 

 served luminescence of the cheek organ of a deep sea luminous fish, 

 Astronesthes ijimai Tanaka (1908), which was collected in a shrimp 

 trawl net in Suruga Bay. This fish has a cheek organ and two rows 

 of minute photophores along the ventral and lateral walls. The struc- 

 ture of the cheek organ is very similar to that of Anomalops. Although 

 luminescence is continuous, the luminous surface appears and disap- 

 pears at will by rotating the cheek organ as in the case of Anomalops. 

 Comparative studies of the structure and substance of both luminous 

 organs should prove interesting. We may find luminous bacteria and 

 a close relationship between the two organs. As deep sea luminous 

 fish are caught with comparative ease by trawlers in many localities 

 in Japan, it is to be expected that many unrecorded luminous species 

 will be found in the future. 



Dr. A. Terao and others (1950) reported a luminous flying fish 

 which was collected from Sagami Bay, Japan. They described the 

 luminous organs as minute, weak, luminescent points scattered on 

 the dorsal surface of the fish and rather strongly luminescent points 

 on the head. The former resemble the skin organ of a luminous shark, 

 and the latter are like the organs of Monocentris. However, I observed 

 several living species of flying fish in the dark at Hachijo Island and 

 Suruga Bay, but could not recognize any luminous points on the 

 surface. 



ACKNOWLEDGMENTS 



I take pleasure in thanking the committee on the Luminescence Confer- 

 ence at Pacific Grove, California, for inviting me to participate in the meet- 

 ings of March 29-April 1, 1954, and express appreciation to Professor E. 

 Newton Harvey for help in preparing this manuscript. 



