Animal Luminescence 587 



Brittle Stars or Snake Stars 



It is possible that Michael Adanson, during A Voyage to Senegal, 

 the Isle of Goree and the River Gambia^^ in 1749-1753, saw lumi- 

 nous brittle stars. He kept fish alive in pails of sea water and saw a 

 pilchard, mole-bat, purple-fish, periwinkle, polypus, crab and star- 

 fish " by rays of light which darted from every part of their bodies." 

 This description sounds as if the light might have been due to 

 micro-organisms in the water, providing the " star-fish " were actu- 

 ally alive and not infected with luminous bacteria. The common 

 forms of true starfish are not luminescent, but one species, Brisingia 

 endecacnemos, dredged by P. C. Asbjornsen in 1856, has been re- 

 ported as luminous, an observation not yet verified. 



In 1805 D. Viviani published a figure of luminous Asterias nocti- 

 luca, which Panceri (1875) identified as a well known brittle-star, 

 Amphiura squamata, and since that time the light of brittle stars 

 has been observed by many naturalists, Peron (1807) Tilesius 

 (1818) and others. Two excellent views (at left, lower; at right, 

 upper side) of a brittle star are shown in Reaumur's plate, figure 49. 



In 1843 A. de Quatrefages published his memoir on luminous 

 annelids and ophiurians, in which he came to the conclusion that 

 the " motor muscles of the feet are the exclusive source of the lieht," 

 which he said appeared in a completely closed cavity in a liquid and 

 that luminescence coincided with contraction and disappeared when 

 contraction has ceased. The luminous strips above mentioned ran 

 parallel to muscle fibers and the light process was quite " indepen- 

 dent of all secretion properly so called." 



Panceri (1878) described the luminescence of Amphiura squa- 

 mata, common in the Gulf of Naples, in a one-page appendix to 

 his monograph, La Luce e Gli Organi Luminosi di Alcuni Annelidi. 

 His figures indicate that only the arms are luminous, the light 

 coming from two oval luminous dots on each segment, near the 

 points where the tube feet arise. When stimulated, the ophiurans 

 gave repeated flashes of light and then scurried quickly away with- 

 out lighting. Consequently Panceri was inclined to doubt the 

 validity of Quatrefages' alleged parallelism between muscle contrac- 

 tion and luminescence, especially as Peron had described an Ophiura 

 phosphorea from the island of Bernier, which luminesced not only 

 on the arms but also on the disc where there were no muscles. 

 Panceri hoped to observe young ophiurians, whose tissues would 

 not be so opaque, but his untimely death in 1877 put an end to his 



*»The English translation, London, 1759, p. 183, of Histoire naturelle dii Seneml, 

 Paris, 1757. 



