224 
at Charlottenlund and Klampenborg among Ulva and Enteromorpha. 
It is evident that it requires only a small degree of saltness as it 
has been taken together with Onc/olaimus thalassophygas d. M. on 
the meadow by Hellerup near Øresund. 
Mononchus papillatus Bastian. 
1865. Bastian, p. 101. Pl, TX, fig. 27-28. 
18783: "Bitsch, -p. 76. P, II, fig, 19 4—Db. 
1884. de Man, p. 64. T. IX. fig. 35. 
Evidently this species is very common in Denmark; it has 
been taken at Lynæs, at the Furesø by Frederiksdal, Lyngby Mose, 
Charlottenlund and Kildeskoven. In Jutland it was collected at Kande- 
stederne, in a pond among the dunes by Lønne and at Nymindegab 
opposite to the mouth of Ringkøbing Fjord. It can by no means be 
called ,,ziemlich selten" here such as de Man indicates it to be 
in Holland. De Man notes that it occurs ,,in der feuchten Erde 
auf Wiesen und Marschgriuden sowohl in Siisswasser- als in Brack- 
wassergegenden"; this also agrees with its occurrence in Denmark. 
A curious fact is, that it can be found both in sandy marshland, 
among dunes and in fat mould. 
The Danish form agrees almost perfectly with the description 
of de Man, differing only in the fact that the chitinous list 
situated in the cavity of the mouth opposite to the dorsal tooth is 
slightly serrated, a fact which has not hitherto been observed. 
Mononchus speectabilis n. sp. 
Pl. II. figs. 17, 19, 27, 28, Pl. IV. fig. 36. 
In March 1910 the author 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 
