202 Papers from the Department of Marine Biology. 



between 45° and 54° and returns on cooling. The maximum tempera- 

 ture from which the Hght revived was 84° and it usually returned 

 about 50°, These effects are similar to those observed with Cypridina. 



Very weak concentrations of acids prevent the production of light 

 of the firefly, less weak concentrations of alkalies are necessary, and 

 KCN does not affect light-production in strong (m/100) concentrations. 



Table 10 summarizes the characters of photogenin and photophelein 

 (luciferase and luciferin) as found by Dubois for Pholas and by myself 

 for Cypridina and the firefly. Where a statement runs through both 

 photogenin and photophelein columns it applies to a mixture of the two 

 substances. A blank indicates that the experiment has not been tried. 



STUDIES ON A PENNATULID, CAVERNULARIA HABERI. 

 GENERAL CHARACTERS OF THE ANIMAL AND OF THE PHOTOGENIC MATERIAL. 



Panceri (24), working with Pennatula phosphorea, has given us the 

 best account of phosphorescence among the pennatulids. He de- 

 scribes the light as coming from eight bands of cells on the outer wall of 

 the stomach and continued into buccal papillae. They contain a 

 luminous "fatty" matter which can easily be squeezed out as a sort of 

 slime and which does not decompose readily. He also found that on 

 stimulation a wave of light would pass over the colony in anj- direction 

 at a rate of about 5 cm. per second. In a form like Caver7iularia he 

 describes also somewhat similar conditions (24, p. 40), but his descrip- 

 tions are very meager. I have found the Japanese species of Caver- 

 nularia more favorable for light experimentation than Pennatula, and 

 the following pages contain confirmation of Panceri's experiments on 

 the light-waves passing over the colony and a general account of the 

 chemistry of light-production. 



Cavernularia haberi is especially abundant in the fjord of Aburatsubo, 

 Japan, near Misaki, the marine station of the Imperial University of 

 Tokyo. The colony of animals lies hidden in the sand and contracts 

 during the day, but at night takes up water and expands, large ones 

 to the length of 2 feet. If stimulated by touching or electrically, or 

 by the addition of ammonia, a slime is formed similar to that produced 

 by most of the Cnidaria upon irritation, but differing in that it is 

 brightly luminous. The whole of the outer surface of the colony can 

 form the luminous slime, but not the spongy inner material. The 

 stalk, containing no polyps, is especially brilliant. 



The slime may be dried over CaCl2 and will give light when mois- 

 tened with sea-water or fresh water. 



By squeezing Cavernularia, from which most of the sea-water has 

 been gently pressed, one can easily obtain a luminous juice which is 

 still luminous when filtered through filter jjaper and retains its lumi- 

 nescence for several hours. Examination of the filtrate under the mic- 

 roscope in the dark shows that the light comes from minute points of 



