ON THE WINTER NEST OF THE HARVEST MOUSE. 235 
fishes, and other animals, seeks nests and eggs of birds, and 
gathers all sorts of objects from the sea-shore. During the whole 
year he was to go to the spot every week in order to observe the 
little mice in question, and to extend his excursions in search for 
others for several miles in the neighbourhood, whereas I myself 
from time to time visited the field of our observations. 
It soon appeared that the reeds of the ditch contained about 
fifty nests of the Harvest Mouse, that isolated nests were found in 
the neighbouring lanes, scattered here and there in herbs growing 
amongst the brushwood, and that a small part of the colony had 
established itself, likewise in herbs amongst brushwood, at the 
distance of about a mile from the principal colony, occupying the 
reeds of the ditch. The nests of this smaller colony were like- 
wise scattered in places fit for the purpose, and their number 
observed did not exceed about twenty. 
The discovery of so considerable a number of the curious 
nests of the Harvest Mouse, in a comparatively limited space, 
afforded great satisfaction, the more so as a previous and active 
search after them during forty-three years had led to no other 
result than the discovery of two such nests: the one found, in 
the year 1853, among the branches of a shrub of Hippophaé 
rhamnoides, on the dunes to the north of the village of Noordwijk- 
upon-Sea; the other, found in the year 1854, placed in one of the 
oak-shrubs growing southward of the aforesaid locality, about a 
mile distance from the sea-shore. 
Wishing to preserve from destruction the colony of this 
interesting little animal, established in the neighbourhood of my 
residence, I selected for our collection no more than about twenty 
nests, showing the different modes of variation which they present 
in general. 
I must state beforehand that the ditch concealing the largest 
number of nests of the Harvest Mouse was also inhabited by a 
couple of Calamodyta arundinacea and by another couple of 
C. phragmitis, that two couples of C. palustris had established 
themselves in the herbs of the immediate outside border of the 
reeds, and that the nests of all these birds were found and 
collected. 
The nests of the Harvest Mouse are in general of a globular 
form, of the average size of a man’s fist, and show, on one side, 
somewhat towards the top, a circular opening sufficiently wide for 
