Animal Luminescence 589 



Mediterranean. In more modern times the luminous organs of Salpa 

 were certainly seen by Peter Forskal, friend of Linnaeus, who first 

 accurately described Salpae in 1775 and proposed the generic name. 

 Forskal did not know that certain clumps of cells in the animal 

 were luminous, and their function has given rise to much specula- 

 tion, being regarded as ovaries or renal organs. According to Ehren- 

 berg (I834),A. Chamisso (1781-1839) saw luminous Salpae in 1819, 

 while S. Delle Chiaje (1828) declared them non-luminous. How- 

 ever, W. Baird (1831) , in his article " On the Luminousness of the 

 Sea," recorded a Salpa as emitting light and his figures depict what 

 were evidently Salpae. All animals retained their " luminous prop- 

 erty for upwards of 12 hours after they were placed in a tumbler 

 of clear salt water." 



F. D. Bennett (1837) and many naturalists since then have spoken 

 of the luminescence of Salpa while E. H. Giglioni (1870) saw the 

 light of Doliolium and Appendicularia, on a voyage around the 

 world in 1865-1868. As with so many other luminous animals, 

 P. Panceri (1872, 1873) gave the first detailed account of the light 

 organs, with a number of physiological and biochemical observa- 

 tions, while P. Secchi (1872) reported on the spectrum of the light. 

 Elucidation of the complicated life history of the luminous cells 

 during embryonic development, with the possibility that they might 

 contain symbiotic luminous bacteria was an accomplishment of the 

 next century. 



Miscellaneous Marine Organisms 



Among several additional groups of the animal kingdom, reports 

 of luminous forms have appeared from time to time. Some of these 

 may be due to ingestion of luminous food, for example the rotifer 

 seen by G. A. Michaelis (1830) and called a Vorticella. It was later 

 described by Ehrenberg (1834) as Synchaeta baltica, but Ehrenberg 

 was unable to observe the luminescence. 



A luminous flatworm, Planaria retusa, was described and figured 

 by Viviani (1805), but the identification is questionable and the 

 luminosity of this form and other luminous flatworms has not been 

 verified. 



Among arrowworms or Sagittae, two reports of luminosity exist, 

 one by E. H. Giglioni (1870) and one by C. Khvorostansky (1892) , 

 but nothing is known of the light organ. 



Sponges have for many years been regarded as in the doubtful 

 category, as far as luminescence is concerned. Most of the reports 

 have turned out to be luminescence of organisms living on the 

 sponge. However, the author in 1921, found a Grantia-like sponge 



