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LUMINOSITY AND ITS OEiaiN IN A SOUTH AFRICAN 
EARTHWOEM (CHILOTA SP. ?). 
By J. D. F. OiLCHRisT, M.A., Ph.D., D.Sc. 
(With Plate XXIV.) 
Cases of luminosity or phosphorescence in earthworms have from time to 
time been observed. From 1670 (G-rimm) up to the present day there are 
records of such observations. Vejdovsky (1884) found the common earth- 
worm AUolohophora foetida to give out an occasional phosphorescent light, 
from the glandular cells of the epidermis he believed ; and Owiannikow 
(1864) observed Enchijtraeus alhidus, ^vohsihlj identical with Lumbricus noc- 
tilucus of Eversmann (1838), to show a light, which appeared, sometimes 
on the head region, sometimes on the tail, and, at other times, over the 
whole body. According to Flaugergues (1771), the light occurs chiefly at 
the region of the clitellum, and disappears after copulation. Moquin Tandon 
and Panceri (1875) also believed that the clitellum is the source of the 
luminosity. Griard (1887), on the other hand, found small, luminous worms, 
which he calls Photodriliis, and indicates that the source of luminosity is in 
certain glands, which surround the alimentary tract, and open on the back 
of the animal to the exterior. In addition to the authors quoted, others, 
such as Dugcs (1837), Moniez, Stein (1831), Matzdorff (1883), Haupt 
(1903), etc., also mention luminosity in earthworms (see references). 
It does not appear, therefore, that there can be any doubt as to the occur- 
rence of the phenomenon, though there is much diversity of statement as to 
the facts and the probable cause of the luminosity. In view of this uncer- 
tainty, the most recent view on the subject is that the luminosity is brought 
about secondarily, and is probably due to the presence of luminous bacteria 
or fungi in the body of the earthworm. Mangold (1910) suggests luminous 
bacteria or fungi, and he remarks that it is strange that a peculiarity of 
such a striking nature in an animal so common as the earthworm should be 
so little known. The latest reference is contained in Dahlgren's account of 
luminous animals (1916). While he finds many accurate and exhaustive 
accounts of luminosity or luminous organs in other animals, including the 
marine worms, he finds nothing definite to record in the case of earthworms, 
and is inclined to believe that the luminosity is due to the accidental presence 
