Animal Luminescence 591 



Messina and in 1838 used the expression " punti luminosi " or 

 " lucidi " and " apparecchio lucido " for the skin structures. His 

 figures show the photophores clearly and he worked in a region 

 where the light of the living fish could have been observed. Never- 

 theless, the great histologist, Rudolf Albert Kolliker (1817-1905), 

 thought the skin spots of deep sea fish were sense organs in 1853, 

 while Rudolph Leuckart (1822-1898) in 1865 regarded them as 

 accessory eyes (Nebenaugen) . They were called modified eyes in a 

 long paper by M. Ussow as late as 1879. 



In the meantime, F. D. Bennett (1840) , during a whaling voyage 

 around the world in 1833-1836, had described the glow from a living 

 shark, kept in an aquarium for three hours, and Franchesco Orioli 

 wrote De Pesci e del Mare che Rilucono Nella Oscurita in 1850. 

 It is quite certain that J. T. Reinhardt (1854) saw the greenish 

 luminescence of fish photophores of the genus, Astronestes, during a 

 voyage to Brazil. 



However, it was not until the deep sea expedition of the " Chal- 

 lenger " (1873-1876) that scientists generally realized how large the 

 deep sea fish population is and how many of them are luminous. 

 Discussion of the skin spots continued, and in 1879 Franz Leydig 

 (1821-1905) designated the " Nebenaugen " of Chauliodus as prob- 

 able luminous organs. In his book Die Augenahnlichen Organe der 

 Fische (Bonn, 1881) , he became convinced that their function is 

 photogenic. 



Since then the various deep sea expeditions have added enorm- 

 ously to the number of luminous species known to science and many 

 observations of light from the " pearly spots " have confirmed their 

 function as light emitting, not light detecting. C. Emery (1884) 

 and R. von Lendenfeld (1887) were pioneers in study of the 

 histology of the light organs, followed by a host of workers at the 

 turn of the century. 



In recent times it has been discovered that a number of fishes are 

 not self-luminous, but possess special organs in which symbiotic 

 luminous bacteria are cultivated. These bacteria are always present 

 and the light organ a permanent structure, often of complicated 

 make-up, with reflectors and devices for shutting off the light. The 

 first inkling of the presence of bacteria was contained in a short note 

 of B. Osorio (1912) regarding the macrurid fish, Malacocephalus 

 laevis, which when disturbed, secretes the luminous bacterial mass 

 through a duct. The second observation was made by the author 

 (Harvey, 1921) for the fishes, Anomalops and Photoblepharon of 

 the Banda Islands, Indonesia. These forms possess a large perma- 

 nent light organ containing luminous bacteria under the eye. The 



