OXYGEN AND LUMINESCENCE. 95 



same statement of the extract of luminous bacteria for luminous 

 material cannot be obtained apart from the living bacterial cell. 

 The same is probably true of luminous fungi. They (Panus 

 stipticus) require oxygen for luminescence. If ground in a 

 mortar, Panus stipticus luminescence ceases almost immediately, 

 so that an extract cannot be obtained. 



The work of many investigators has shown that luminous 

 extracts of Pholas (lamellibranch mollusc), Cypridina (ostracod 

 crustacean), fireflies, Cavernularia (pennatulid), Photoblepharon, 1 

 Anomalops, 1 and Malacocephalus (fish) require oxygen for lumi- 

 nescence. I have recently investigated the following forms using 

 extracts of the animals whenever possible. 



Microscolex phosphor ea, an earthworm producing a slime on 

 stimulation, brightly luminescent with a yellowish light. The 

 worm can be dried over CaCU and gives a bright light on 

 moistening with water. Worms shaken in pure hydrogen give 

 no luminescence but produce a slime which luminesces im- 

 mediately when air is admitted. 



Chaetopterus variopedatus, a polychaete producing a slime with 

 bluish light on stimulation. In sea water the luminescence of 

 the slime lasts long enough for one to observe the disappearance 

 of luminescence when pure hydrogen is bubbled through it and 

 the reappearance on admitting air. 



Acholoe astericola, a polynoid worm whose scales emit a bright 

 yellowish luminescence on stimulation. The light comes from 

 groups of gland cells under the cuticula ending in a papilla with 

 a pore, but not enough secretion is extruded to form a luminous 

 solution. The whole animal when slowly heated in sea water or 

 shaken gives a bright luminescence (over the scales) but if 

 slowly heated or shaken in sea water with platinized asbestos 

 through which hydrogen is passed, there is no luminescence. 



Thelepus cincinnatus, a polychaete allied to Polycirrus, produces 

 a luminescent slime on handling. When the whole worms are 

 placed in a tube through which pure hydrogen is bubbled the 

 luminescence disappears, but returns again when air is admitted. 



Amphiura squamata, a brittle star whose arms produce a 

 yellowish luminescence. The individual gland cells lie beneath 



1 The light of these forms is due to symbiotic luminous bacteria living in the 

 organ. 



