XI. Mathematical contributions to the theory of evolution. —X. Supplement to a memoir on skew variation

(1.) In a memoir on Skew Variation published in the ‘Phil. Trans.,’ A, vol. 186, 1895, a series of frequency curves are discussed which are integrals of the differential equation 1/y dy/dx = -x /c 1 +c 2 x +c 3 x 2 . . . . . . (i.). (See P. 381 of the memoir.) The discussion of four main types is given in detail, and a brief reference is made to various sub-types which may occur. The types considered in that memoir covered at the time all the frequency series, and they were fairly numerous, that I had had occasion to deal with.