224 
at Charlottenlund and Klanipenborg among Ulva and Enteromorpha. 
It is evident that it requires only a small degree of saltness as it 
has been taken together with Oncholaimus thalassophygas d. M. on 
the meadow by Hellerup near Oresund. 
Mononchus papillatus Bastian. 
1865. Bastian, p. 101. PI. IX. fig. 27 — 28. 
1873. Biitschli, p. 76. T. III. fig. 19 a—b. 
1884. de Man, p. 64. T. IX. fig. 35. 
Evidently this species is very common in Denmark; it has 
been taken at Ly næs, at the Furesø by Frederi ksdal, Lyngby Mose, 
Charlottenlund and Kildeskoven. In Jutland it was collected at Kande¬ 
stederne, in a pond araong the dunes by Lønne and at Nymindegab 
opposite to the mouth of Ringkøbing Fjord. It can by no means be 
called „ziemlich selten“ kere such as de Man indicates it to be 
in Holland. De Man notes that it occurs „in der feuchten Erde 
aufWiesen und Marsckgruuden sowohl in Siisswasser- als in Brack- 
wassergegenden“; this also agrees with its occurrence in Denmark. 
A curious faet is, that it can be found both in sandy marskland, 
among dunes and in fat mould. 
The Danisk form agrees almost perfeetly with the description 
of de Man, differing only in the faet that the ckitinous list 
situated in the cavity of the mouth opposite to the dorsal tooth is 
sligktly serrated, a faet which has not hitherto been observed. 
Mononchus spectabilis n. sp. 
PI. III. figs. 17, 19, 27, 28, PI. IV. fig. 36. 
In March 1910 the autkor found in some material from the 
meadow by Hellerup near Oresund several Mononchs resembling 
highly the Mononchus papillatus , only conspicuously larger and, 
what is the most remarkable, the males being about as numerous 
as the females. 
All the species of the genus Mononchus show the peculiarity 
that they will float on the surface of the water as if their cuticula 
