Danish freeliving Nematodes. 
By 
Hjalmar Ditlevsen, 
Zoological Museum, Copenhagen. 
The present paper is a contribution to the knowledge of the 
freeliving Nematodes of Denmark, a part of our fauna to which 
almost no attention has been paid till now. It treats 59 species, 
distributed on 21 genera. The great majority are land- and fresh- 
water species. I have included a few marine littoral forms which 
I met with accidentally, e. g. Rhabditis marina which Bastian 
described in 1866 from Falmouth. 8 species have not been de- 
scribed before. 
Though the work is mainly faunistic there are included some 
observations of biological and morphological facts. Such facts will 
be found under the respective species. 
All the animals dealt with were collected by the author. 
Consequently the majority originate from the surroundings of Copen- 
hagen. A smaller part was taken near the mouth of the Isefjord, 
near Lynæs. The Jutland-forms I collected on a journey last sum- 
mer (1910) at the expense of the Japetus Steenstrup fuud, for 
which beg to offer my best thanks. 
I am much indebted to the Carlsberg fund for the support it 
has given my work by enabling me to procure suitable instru- 
ments, and also for having paid the phototypic reproduction of 
the plates. 
I wish to thank Dr. de Man in Yerseke for the kindness 
with which he has plåced at my disposal his great knowledge 
whenever I have addressed myself to him. 
