Animal Luminescence 581 



lished a large monograph dealing with all aspects of light produc- 

 tion in Pholas dactylus in 1892. In the same year a histological study 

 of Pholas also appeared in German by B. Rawitz (1892) , from the 

 University of Berlin. 



It is interesting to note that Dubois was quite up to date in his 

 use of the word " luciferase." Although W. Kuhne had suggested 

 that unorganized ferments like ptyalin and pepsin be called 

 " enzymes " in 1878, it was not until 1883 that Emile Duclaux 

 introduced the termination " ase " added to the substrate on which 

 the enzyme acted to designate the enzyme itself. Four years later 

 Dubois was using luciferase in connection with luciferin. 



Nudibranchs 



According to Ehrenberg (1834: 498) , F. S. Leuckart (1794-1843) 

 in 1827 saw both Aplysia and Doris luminesce, but the animals were 

 dead and the light probably due to luminous bacteria. A second 

 statement may refer to nudibranchs but the reference is uncertain. 

 The Reverend Wm, Kirby, co-author with Wm. Spence of the 

 famous Introduction to Ejitomology (1817) , wrote another book in 

 1835, The Creation of Animals and Their History, Habits and 

 Instincts. In this book Kirby mentioned violet snails (lanthina *^ 

 of Bosc) which float at the surface of the sea and color the water 

 with a blue fluid when disturbed and " are vividly phosphoric at 

 night." 



R. T. Lowe (1842) found a nudibranch called Peplidia (now 

 Plocamopherus) at Madeira, and studied the method of movement 

 and the luminescence for some days. He wrote, " At night, espe- 

 cially when thus in motion, it appeared most brilliantly phospho- 

 rescent; the light flashing progressively but very rapidly along the 

 body, especially from all the branchial tufts and the edges of the 

 veil and crest." Another record is of a luminous Tethys fimbria, 

 seen by A. E. Grube (1812-1880) along the Dalmation coast in 1861. 



The most famous luminous nudibranch, Phillirhoe bucephala, has 

 been known since 1807. It was named by Francois Peron, but no 

 one noticed the luminescence until 1873 when Paolo Panceri's 

 monograph appeared. He wrote: 



... if the water in which they are found be agitated, or if they are 

 touched, flashes of light will be seen to come from their body; and if, 

 for the purpose of provoking the complete illumination of the phospho- 

 rescent elements of the Phyllirrhoe, one stimulates it with a drop of 



*^ The lanthinidae float at the surface of tropic seas and expel a violet secretion 

 when disturbed, which might appear like a phosphorescence. 



