219 
den einzelnen Klumpen und an den Wånden des Gefåsses hinziehen; 
andere ballen sich zu Klumpen zusammen, in welchen sich viele 
Hunderte der Thierchen umeinander herumwinden“. The description 
Biitschli gives of the behaviour of this species reminds one of 
othei Nematodes ot putrefaction, for instance Rhabditis and Diplo - 
gaster , which foims it resembles as to the great number of eggs 
which it produces. It is ovoviviparous, a faet that is often observed 
among the Bhabditides, and the body of the female is frequently 
swarming with large young. 
I have found this species both in the Kalkbrænderihavn near 
Copenhagen and at Charlottenlund. And even if I have not seen 
it in such lots as Biitschli describes, my opinion is that it is 
a iathei common littoral-form which will appear in putrefying sea- 
weed and which probably can be found all round our coasts. 
Monohystera rrassissima n. sp. 
PI. III. Figs. 14. 15, 22. 
I found the species for the first time in July 1909 among' 
Conferves from a pool on the meadow near Øresund by Hellerup. 
As the mateiial had been standing for a few davs in a Petri-cup 
and began to putrefy I remarked that the individuals of the Nema¬ 
todes inereased conspicuously in number and after some days more 
I had a regular culture. This only kept for a while; when the 
putrefaction augmented the animals died rather speedily. Later I 
have taken the species several times at the same localitv but al- 
ways only single individuals and I have not succeeded in my 
attempts at getting a culture anew. I suppose that we here have 
to do with a typical Nematode of putrefaction like M. socialis 
Biitschli, the single specimens I have met with later on being young, 
immature individuals roamingabout. 
The shape of this species is extraordinarily clumsy but it is 
very agile and has some resemblanee to diminutive fiy-maggots, 
which is particularly striking where it is found in abundance. It 
has its a\eiage width about the middle of body and is tapering at 
