Animal Luminescence 571 



Sea Pens 



Although sea pens were known to the ancients, and were called 

 by the Romans Penna marina (sea feather) or Mentula alata (winged 

 penis) , no special attention was paid to their luminescence until the 

 time of Rondelet (1554) and Gesner (1555). Gesner mentioned 

 the light both in De Lunariis and in the Historia Animalium, while 

 Boussuet (1558) sang of their glitter. The Rondelet-Aldrovandi 

 (1613) wood cut of the Penna marina is reproduced in figure 2. 



Later the sea pen was seen and mentioned, among others, by such 

 naturalists as Johannes Jonstonus (1603-1675) in Historia Natumlis, 

 de Exsanguibus Aquatis, libri IV (1650) . He published a beautiful 

 woodcut of Penna marina with the description, " Noctu maxime 

 splendit, stellae modo, ob candorum et laevorum." 



In the eighteenth century many books refer to the light of the sea 

 pen. Thomas Shaw (1692-1751), the divine who became Regius 

 Professor of Greek at Oxford, published his Travels or Observa- 

 tions Relating to Several Parts of the Barbary and the Levant in 

 1738. He wrote: -^ 



The fishermen find, sometimes, in drawing and clearing their nets, the 

 penna marina or sea feather; which in the night time particularly is so 

 remarkably glowing and luminous, as to afford light enough to discover 

 the quantity and size of the fish that are enclosed along with it in the 

 same net. 



Probably the first indication of deep-sea life came with the dis- 

 covery of a pennatulid, Umbellularia groenlandica, caught on a 

 sounding line at 300 fathoms by M. Christlob Mylius in 1754, off 

 the coast of Greenland. This form, which is luminous, was de- 

 scribed by John Ellis (1763) and later rediscovered by M. Lindahl 

 in the Northern Ocean.^° 



Linnaeus said of Pennatula phosphorea: " Habitat in Oceano, 

 fundum illuminans," while writers on zoophytes such as J. B. 

 Bohadsch (1761), John Ellis (1763), P. S. Pallas (1766), L. Spal- 

 lanzani (1784), and J. Ellis and D. C. Solander (1786) all devote 

 considerable space to the light of sea pens. Ellis (1763) described 

 the " kidney shaped pinple sea pen from South Carolina," a Renilla, 

 but did not mention its luminescence. The Ellis drawings are repro- 

 duced as figure 48. In 1850 Louis Agassiz was impressed with its 

 " golden green light of a wonderful softness." 



As in so many other fields of science, Spallanzani's observations 



2»2nd ed. 1757, p. 191. 



'"See Voyage of the Challenger, by C. W. Thomson 1: 151, 1877. 



