ON THE NEMATODES OF THE COMMON EARTHWORM. 607 
good figures. He noticed certain structural differences 
between bis form and Schneider’s but regarded these as un- 
important. He altered Schneider’s name Pelodera pellio 
to Rhabditis pellio, Rhabditis being Dujardin’s name 
for the larvte which he found in the eartliworm. 
Von Linstovv (3) in 1882 described the larvae as well as the 
adult males and females, and, using a decaying worm, actually 
developed the encysted larvae into the sexually matui’e Rh. 
pellio. 
Railliet (7) in 1893 merely quoted Schneider’s description. 
Keng (8) in 1895 watched the eucystment of the coelomic 
form, but he does not show that he was aware of the identity 
of the nematodes with which he was dealing. 
In 1897 von Erlanger (9), working on the segmentation of 
the egg, made a pure culture of Rh. pellio from strips of 
the body -wall of an earthworm placed on soil which had 
been first sterilised and then moistened. He obtained large 
numbers in this way. 
Maupas (10) in 1899 made extensive cultures of Rh. pellio 
with an artificial food-medium. He probably used for parents 
the encysted larvae from the freshly killed worm or the mature 
adults from decaying worms, for, while he speaks about the 
encysted, coelomic form, strangely enough he does not mention 
the active, nephridial larvae. 
In 1900 de Ribaucourt (11) described the excystation of 
the encysted larva. He mentions the nephridial foi'm and 
explains its probable method of entry. He did not attempt 
to determine its identity or show that he knew that of the 
encysted form, but he evidently regarded them as belonging 
to the same species. 
Shipley (12) in 1902 summarised the work of the earlier 
writers. Like them he says nothing of the nematode in the 
nephridia. 
K. C. Schneider (13) in 1902 mentioned the encysted larvae 
of Rh. pellio occurring in the coelom. He also says that 
nematodes, which, according to Anton Schneider, belong to 
Rh. pellio, are frequent in the lumen of the bladder of the 
