TRANSACTIONS OF THE SECTIONS. 69 
Description of a Chart of the Natural Affinities of the Insessorial Order of 
Birds. By H. E. StRIcKLAnp. 
At the Glasgow meeting, in 1840, Mr. Strickland had first proposed his plan for 
exhibiting the affinities of allied organic forms, by a process analogous, in some re- 
spects, to that of map-making. He now exhibited a large chart constructed on this 
plan, and showing the affinities of the genera in the order Insessores. The name 
of each genus is inscribed in an oval cartouche, and its affinities to other genera are 
indicated by connecting lines, the lengths of which lines are approximately propor- 
tionate to the remoteness of the affinities. Those genera which are most nearly allied 
are connected by a line of one degree, or unit, in length; and those less closely allied, 
by a line of two degrees. Genera so distant as to require to be placed in different 
sub-families, are united by lines of three or four degrees; those in different families 
by lines of five or six degrees; and those in different tribes by lines of seven or eight 
degrees. A line is drawn round those genera which constitute one sub-family, and 
the area thus inclosed is coloured, the surrounding space being left white. The sub- 
families which belong to the same family, are distinguished by the same colour; and 
the families are inclosed within a dotted line; while the boundaries of the tribes 
are marked by a red stripe. The names of the respective groups are inserted; and 
the whole assumes the appearance of a cluster of islands depicted on a map. The 
author expressed his belief that the true affinities of organized beings may be ex- 
pressed with greater accuracy and conciseness by this method than by any other with 
which he was acquainted. Being a purely inductive process, the details of any 
branch of natural history may be in this way worked out and depicted without re- 
course to any theoretical assumptions. One result of it seems to be, that the true 
affinities of organic structures branch out irregularly in all directions, and that no 
symmetrical arrangement or numerical uniformity is discoverable in the system of 
nature when studied independently of preconceived theory. ' 

Periodical Birds observed in the years 1842 and 1843 near Llanrwst, Den- 
bighshire, North Wales. By Joun Buacxwatt, F.L.S. 

Birds. Appeared. | Disappeared. 
1842. 1843. 
Redwing, Turdus iliacus ..........+. “SCTE LAR, Oct. 
Woodcock, Scolopax rusticola ..........00.see seer eeeees ” 7 | March 25 
Mountain Finch, Fringilla montifringilla ..............+. iat >) 
Fieldfare, Turdus pilars ............4. Reet rene. Nov. 6] April 5 
1843. 
Pied Wagtail, Motacilla alba ....... Reps orice ses 4 March 13 
Yellow Wren, Sylvia trochilus ......0+ccce.seeeeseceeess April 10 
Common Sandpiper, Totanus hypoleucos ...,.......+ aipiare 3 11 
Redstart, Sylvia phoenicurus ........00ceeeeeees AO GEE 2 16 
Swallow, Hirundo rustica ............ Bate carne tis oeacaiesers ee 16 
Sand Martin, Hirundo riparia ........ [da dno ane P Re ready 
Tree Pipit, Anthus arboreus ......+....- SE epioche Ea eae Ae gel a ee 
Cuckoo, Cuculus canorus ........ hincwon, oi: Botete eae ets es 20 | July 3 
Lesser Pettychaps, Sylvia hippolais ............. emo tys Ment tiles Wes | 
Black-cap, Sylvia atricapilla............ Lapel es et bt say ae 
White-throat, Sylvia cinerea... ..........00ee eee eg ae Be 23 
Wood Wren, Sylvia sibilatrix ........ Ma eersee a tlamiel Me cies ey 24 
Land Rail, Gallinula crez ...... Si Sek er Aad Nae 3 24 
Whinchat, Sazicola rubetra ...... Wenestts SME Scie ait ote F i 29 
Pied Flycatcher, Muscicapu luctuosa ...........0..eeeeee May 2 
Swift, Cypselus murarius ........+0...065 OE RAB Ar a3 5 | Aug. 10 
House Martin, Hirundo urbica........ 0002. c cece eee ee es ne 6 
- Pettychaps, Sylvia hortensis .......... pe stolalatturata rare seelonet » 9 
Sedge Warbler, Sylvia phragmitis .....+..0+.... er ca tees 10 
Red-backed Shrike, Lanius collurio .......... Soa. weaes op 1] 
Spotted Fly-catcher, Muscicapa grisola ......s0..seeese0 | 9 14 
. Goat-sucker, Caprimulgus europ@us .....ceeereveccescne ” 19 
