Chap. XXVI. ANALOGOUS VARIATION. 341 



hazel, and barberry have given rise to purple-leaved varieties; and 

 as Bernhardi remarks, 27 a multitude of plants, as distinct as possible, 

 have yielded varieties with deeply-cut or laciniated leaves. Varieties 

 descended from three distinct species of Brassica have their stems, 

 or so-called roots, enlarged into globular masses. The nectarine is 

 the offspring of the peach; and the varieties of peaches and 

 nectarines offer a remarkable parallelism in the fruit being white, 

 red, or yellow fleshed — in being clingstones or freestones — in the 

 flowers being large or small — in the leaves being serrated or crenated, 

 furnished with globose or reniform glands, or quite destitute of 

 glands. It should be remarked that each variety of the nectarine 

 has not derived its character from a corresponding variety of the 

 peach. The several varieties also of a closely allied genus, namely 

 the apricot, differ from one another in nearly the same parallel 

 manner. There is no reason to believe that any of these varieties 

 have merely reacquired long-lost characters ; and in most of them 

 this certainly is not the case. 



Three species of Cucurbita have yielded a multitude of races 

 which correspond so closely in character that, as Naudin insists, 

 they may be arranged in almost strictly parallel series. Several 

 varieties of the melon are interesting from resembling, in important 

 characters, other species, either of the same genus or of allied genera ; 

 thus, one variety has fruit so like, both externally and internally, 

 the fruit of a perfectly distinct species, namely, the cucumber, as 

 hardly to be distinguished from it; another has long cylindrical 

 fruit twisting about like a serpent ; in another the seeds adhere to 

 portions of the pulp; in another the fruit, when ripe, suddenly 

 cracks and falls into pieces ; and all these highly remarkable 

 peculiarities are characteristic of species belonging to allied genera. 

 \Ye can hardly account for the appearance of so many unusual 

 characters by reversion to a single ancient form; but we must 

 believe that all the members of the family have inherited a nearly 

 similar constitution from an early progenitor. Our cereal and many 

 other plants offer similar cases. 



With animals we have fewer cases of analogous variation, inde- 

 pendently of direct reversion. We see something of the kind 

 in the resemblance between the short-muzzled races of the dog, 

 such as the pug and bull-dog ; in feather-footed races of the fowl, 

 pigeon, and canary-bird ; in horses of the most different races pre- 

 senting the same range of colour ; in all black- and-tan dogs having 

 tan-coloured eye-spots and feet, but in this latter case reversion 

 may possibly have played a part. Low has remarked 28 that several 

 breeds of cattle are " sheeted/' — that is, have a broad band of white 

 passing round their bodies like a sheet ; this character is strongly 

 inherited, and sometimes originates from a cross ; it may be the 

 first step in reversion to an early type, for, as was shown in the 



27 ' Ueber den Begriff der Pfianzen- 28 < Domesticated Animals,' 1845, 



art,' 1834, s. 14. p. 351. 



