236 THE ZOOLOGIST. 
the entrance of the little animal. The nests found in the ditch 
were commonly placed towards the top of the reeds; for those 
built on the outside of the water and in the shrubs the animals 
had chosen gramineous plants and all sorts of herbs, especially 
Rubus fruticosus, Rumex acetosa, and Epilobium. It happens even 
that our little animal, probably pressed by the necessity of bringing 
forth its progeniture, accommodates for this purpose one or the 
other bird’s nest within its reach by covering these nests with a 
cap of grass. In the two instances observed of this kind, one of 
the nests belonged to Calamodyta arundinacea, the other to Sylvia 
cinerea, the latter one still containing the broken eggs of the bird. 
Several nests contained the still naked young mice. As to 
the old mice, there was no other way to get hold of them than 
catching them with the hand while they were in their nest or about 
to enter it; and even in this way chance alone could ensure 
success, the movements of the little creature being performed 
with surprising agility; even whilst climbing their tail is partly 
twined about the reeds or branches—a pecularity also observed 
by Pallas with respect to Mus vagus and M. betulinus. It was in 
vain that we set traps of different structure and provided them 
with all kinds of bait. Mus sylvaticus and M. musculus were from 
time to time caught in those traps, but not a single M. minutus. 
I think it worth while to mention here the singular fact of a 
specimen of Mus minutus observed in the year 1851, as a straggler 
in the middle of the town of Leyden. A living specimen of this 
mouse having been caught in a trap of iron network placed in a 
room was brought to one of the inhabitants, then a student at 
the University. This gentleman, Mr. R. ‘I’. Maitland, as an 
experienced naturalist, at once recognised the species, and seeing 
that the specimen was a pregnant female, he shut it up in a bird’s 
cage, at the same time putting into it a quantity of paper-shreds, 
cotton, and other soft matter. The little animal soon afterwards 
began to build a nest in the wonted globular form, and to deposit 
in it two young ones. 
I now return to our colony of mice in the ditch. After the 
breeding season the reeds of the ditch were cut down, with the 
exception of a small patch of reeds in the middle of the ditch and 
beyond the reach of the mowers. We then saw, to our great 
astonishment, that our little mice established between these reeds 
nests of a very different character from those destined to receive 
