1901. Reviews. . 45 



A SCIENTIFIC ANNUAL. 



"Knowledge" Diary and Scientific Handbook for 1901. 



Pp. 408 and 120. London: Knowledge Office. Price, 3^. net. 

 The publishers of our contemporary, Knowledge, have started the new 

 century with an " Annual," which, though primarily intended for the 

 use of students of astronomy, will be found of value to scientific readers 

 generally. The diary gives the whole of a large page to each day, and 

 may be made a storehouse of MS. notes. There is a comprehensive 

 history of the past century science, in which biology and geology find 

 their full share of recognition, illustrated by portraits of Darwin, Lyell, 

 and Huxley. The star-maps for each month, and the other astro- 

 nomical information will enlarge the outlook of the naturalist by 

 inducing him to take an interest in the heavens above as well as in the 

 earth and sea and all that in them is. We note that a total solar eclipse 

 is to be visible in eastern Ireland in 1927 ! We hope that we ourselves, 

 Knowledge, and the new Annual may be here to see it. 



IRISH MAMMALS. 



I. On Geographical and Individual Variation in IVtus 

 sylvaticus and its allies. By G. E. H. Barrett- Ham ii/Ton, 

 F.z.s. 2. On the Variable Hare (Lepustimidus). By G. E. H. 



Barrett- Hamilton, f.z.s. (Proc. Z00L Soc, 1900.) 



In an able paper on the geographical variation of the Long-tailed 

 Field Mouse, Mr. Barrett-Hamilton distinguishes nineteen forms or 

 races of that widely-distributed species. Five of these (besides an 

 extinct form, Mus Lewisi, known only in a fossil state from Ightham 

 fissure) occur in the British Isles ; but in Ireland only two have been 

 found, to which Mr. Barrett-Hamilton applies sub-specific names as 

 Mus sylvaticus intermedins and M. s. celticus. The former is the generally 

 dominant race throughout the British Isles and Western Europe, and 

 probably prevails throughout all the eastern and midland counties of 

 Ireland. In parts of Kerry and Galway, however, it is replaced by a 

 small dark mouse, which was first noticed by Jenyns in 1S41 ; and on 

 this little animal Mr. Barrett-Hamilton bestows the appropriate name of 

 Mus sylvaticus celticus. 



It is of great interest to find from the paper before us that this mouse 

 of the western parts of Ireland has been ascertained to occur also in the 

 islands of Lewis and Skye. Thus its distribution would appear to be in 

 some sense analogous with that of our Irish Black Rat (Mus hibtrnicus, 

 Thompson), which is met with outside this country in several of the 

 Outer Hebrides. As a tendency towards melanism has been traced in 

 other animals, both in Ireland and the Hebrides, the probability of a 

 positive climatic stimulus in this direction is at first sight considerably 

 strengthened by the addition of Mus celticus to the Hebridean fauna 

 Mr. Barrett-Hamilton himself inclines to the opinion that this dark 



