the common denominator in a manner which makes it unlikely that any of them is closer to macrocephala, than is multicolor. The two species are similar in general size and proportions, the larger size of macrocephala being probably correlated with the cooler climate of New Zealand and the relatively long tarsus with “insular” conditions. Within each species a similar type of geographic variation is shown. Thus, smaller races tend to inhabit warmer localities (Bergmann's Law) and a longer tarsus is found in some outlying insular races. Variation in female, rather than in male, plumage (heterogynism), differences in size of frontal spot and intensity of breast colour, and a tendency for the usual sexual dimorphism in plumage to be lessened by the development of “advanced” plumage in females: these are important phases of geographic variation shared in both species. There are however a few discrepancies. The very large frontal spot of multicolor is shared by goodenovii, and the small spot of macrocephala is present in the remaining Australian species. In multicolor however the frontal spot varies geographically, and at its smallest (campbelli) is not much larger than its best development in macrocephala. On the whole it seems reasonable to consider a small frontal spot primitive and to regard the large spot as a secondary development in multicolor and in goodenovii. Orange-yellow soles characterise the feet of macrocephala. Among Australian species rhodinogaster has “soles of feet ochraceous” (North, 1903) and rosea has “feet dark brown, soles yellow” (specimen so labelled in Serventy-Whittell Collection), but goodenovii has dark soles and P. multicolor campbelli has “feet black, soles grey” (Serventy-Whittell Coll.) and so has the New South Wales race, judging from skins. Two skins of the Samoan P. multicolor pusilla Peale and two of the Fijian P. m. kleinschmidti Finsch have been seen; the soles of their feet had definitely been yellow or orange in life and Dr E. Mayr (pers. comm.) has informed me that the San Cristabel birds (P. m. polymorpha Mayr) collected by him had orange soles. A watercolour sketch of a specimen in the flesh of the nominate race of multicolor, made by Mr A. A. Thompson at Norfolk Island in 1944 and lodged in the Dominion Museum, Wellington, shows distinctly ochraceous but not bright orange soles to the feet. Apparently, therefore, pale yellowish or orange soles are normal in the genus and the darker pigmentation of the continental Australian races of multicolor and of goodenovii is secondary.* As the Australian races of multicolor and the species goodenovii share both large frontal patches and dark (grey or black) soles to the feet, they may be more closely related than their difference in size and habitat preference (and habits?) would suggest. P. goodenovii is tolerant of much greater aridity than multicolor and may have arisen comparatively lately by geographic isolation of part of the multicolor population in an arid area, and attained a sympatric relationship by subsequent expansion and overlap. In size goodenovii is as close to the Pacific races of multicolor as they are to continental multicolor. Petroica macrocephala macrocephala (Gmelin). Yellow-breasted Tit 1789. Parus macrocephalus Gm., Syst. Nat., vol. 1, pt. ii, p. 1013 (Queen Charlotte Sound). 1826. Pachycephalus? auslralis Stephens, in Shaw's Gen. Zool., vol. xiii (2), p. 207 (n.n. for macrocephalus). 1843. Miro forsterorum Gray, in Dieffenbach's Travels in N.Z., vol. ii, p. 191 (Queen Charlotte Sound).