WCP4032

[1]

Holly House, Barking. E[ssex].

January 9^th. 1871

Dear Newton

Will you be so good as to look over the enclosed list of the families of Birds,¹ and let me have any notes that may occur to you as to their equality of value. I find it quite useless to do any work at Geog[raphical]. Dist[ribution]., till the classification of a group is settled, and as in birds hardly any groups higher than families are confined to one region, the equivalence of the families becomes of high importance in determining what are the most natural regions.

I have divided by double lines the separate orders and by single lines [2] suborders, — or they will be suborders and tribes, if Carinatae and Ratitie are the ² orders of existing birds.

You may also give me your views on the arrangement of the ^{series of} families where you see any thing that may be altered for the better. The chief thing however is the equivalence of groups; and this will depend upon two factors — 1st. Is the group in question characterised by about as much structural peculiarity as other "families", — 2nd. Does it contain within itself any group which differs from it, by this amount of structural peculiarity?

With regard to the families given [3] in my list there will be many differences of opinion, & it is only by getting at these opinions & the reasons on which they are founded that we can arrive at a tolerably equivalent series of families.

Who can you recommend me to send the list to, who would give me an opinion, & whose opinion would be of value?

When we have got these groups fairly equivalent, I believe that a consideration of the distribution of the families of birds, and of the suborders, tribes & families of mammals will easily determine geographical [4]² regions by simple numerical preponderance. If you try to set groups of different rank against each other, — as ^several genera against a whole family, you can never settle anything. Families & higher groups will I think determine Regions & the primary divisions of the earth into which Regions can be grouped; — genera will show, the subregions & Provinces.

Hoping you will find time to criticise my families; —

Believe me | Yours very faithfully | Alfred R. Wallace [signature]

Prof. A[lfred]. Newton