466 MURIDAZ—ORCADENSIS 
At that time, of sixteen females trapped, several were pregnant 
with from two to six foetuses.’ Others taken by Mr Godfrey 
on 8th and 9th August contained fcetuses “the size of peas.” 
Mr Robert Drane? has bred these mice in confinement, and 
states that six received in August 1904 increased to sixteen 
by October. There was then a cessation of reproduction until 
28th February 1905, when two of the females gave birth to 
litters of three and four young respectively. Mr Drane 
definitely ascertained that the period of gestation is, as in other 
species, twenty-one to twenty-two days (one instance). The 
young of one litter opened their eyes and emerged from the 
nest to nibble lettuce leaves on the 12th day. At eighteen 
days old they were independent of their mother, who still, 
however, exercised parental authority and drove them home 
peremptorily if she considered them in danger. 
Mr Kinnear found the mice fond of the roots of a common 
rush,® to obtain which they burrow under the tufts. Mr W. R. 
Ogilvie-Grant took the Sanday form with baits of cheese and | 
bulbs of yellow crocus. In captivity their favourite food is 
grass; next, carrots. Their intelligence appears to be inter- 
mediate between that of the Bank Mouse and the Common 
Grass Mouse, but reports of their amiability vary, no doubt 
according to the manner in which they were treated. They 
may bite if roughly handled, will attack fresh members of their 
own species when first introduced to their cage, and sometimes 
behave with great brutality amongst themselves.* Females 
with young must be isolated to protect the litter from the 
attacks of strange males. 
Mr Millais found that his mice became inactive during cold 
weather. 
Like other Grass Mice, the Orkney Mouse is very palatable. 
Every bird and beast seems to eat it, and dogs devour it 
greedily.° 
1 One contained two ; three contained four ; one contained six. 
2 Fieid, 18th March 1905, 465 ; also in Millais. 
3 Determined by W. Evans as /uscus squarosa. 
4 Drane, of. cit. 5 T. E. Buckley, of. cit. supra, p. 49. 
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