68 
Introduction; Variation. 
male offspring will not be allowed to perpetuate itself it would appear that 
such females will have to breed with the finer males and their harmful effect 
on that sex will be done away with in course of generations , because the 
male qualities are transmitted in part to the female offspring as well as to 
the male. 
Mr. Beddard’s opinion that sexual dimorphism is; mainly dependent upon 
the reproductive organs is based upon such rare cases as that of a hermaphro- 
dite Chaffinch (p. 262) in which one side of the bird was found to be like the 
male in coloration, the other side like the female, with the generative systems 
correspondingly divided^). As bearing upon the same matter may be cited the 
circumstance that old females which have lost their fertility sometimes assume 
the male dress. Such facts appear to be very instructive, perhaps proving that 
the sexual glands themselves through nervous influences determine the coloration 
of the integument, intricate questions, which we are not prepared to discuss 
here. But when Mr. Beddard suggests that the differences in disposition and 
habit of very many males and females are dependent upon the sexual germ glands 
themselves he appears to be contradicted by reasons given antea^ p, 66. 
Exceptional cases. An examination of exceptions often throws more light 
upon a matter than is afforded by the contemplation of the rule. The female of 
the Coucal, Centrococcyx hengalensis.^ is much larger and stronger than the male, 
though of similar coloration; it utters remarkable cries and is not known to take 
any share in incubating the eggs ; the male is small, silent, and it broods on 
the eggs. Moreover the male possesses only one testicle, the left one being 
entirely wanting. The_ conditions have been fully described by their discoverer, 
Bernstein, in the Natunrk. Tijdschr. van Ned. Ind. 1860, pp. 27 — 49, pi. I; and 
mentioned J. f. O. 1859, 185; 1860, 269. (See also, subtus, pp. 219, 220). Ap- 
parently both Darwin, Wallace, and Beddard might claim this case as sup- 
porting their different theories. Darwin, though he seems to have overlooked 
the fact, anticipated the possibility of such a condition: “If we might assume 
that the males . . . have lost some of that ardour which is usual to their sex, 
so that they no longer search eagerly for the females . . . then it is not im- 
probable that the females would have been led to court the males, instead of 
being courted by them” (Descent, p. 207). For Wallace’s view it might be 
claimed that the structural deficiency of the male points to a lower status of 
vitality, sufficient to account for its smaller size and quiet habits. In accordance 
1) The Chaffincli quoted by Prof. Beddard was described by Prof. Weber (Zool. Anzeiger 1890, 508). 
Compare Prof. Cab a ni s’ descriptions of such differently coloured halves in Pyrrhula vulgaris and Colaptes 
mexieanus (J. f. 0. 1874, 344); of v. Rosenberg’s of a Chaffinch with tv/o anterior halves of the body, the one 
in coloration a male, the other a female (M. 0. Ver. Wien 1884 VHI, 87 & plate) and of Kleinschmidt’s 
of a bilateral -asymmetrically coloured specimen of the Common Kingfisher (Abh. u. Ber. Zool. Mus. Dresden 
1898/9 Nr. 2 p. 73, plate III). Also the remarks of Prof. Brandt on Arrhenoidia lateralis (Z. wiss. Zool. 1889 
XL VIII, 107) should be consulted. Lorenz asserted that he had seen a similar case in Tetrao tetrix (see: 
Tichomirow: “On Hermaphroditism in Birds” — written in Russian — 1887 p. 21 note), but we doubt this. 
2) “Hahnenfedrigkeit”. Comp. Meyer: Auer-, Racket- und Birkwild 1887 p. 33, and Abh. Ber. Mus. 
Dresden 1894/5 Nr. 3, as well as Brandt’s paper quoted in note 1. 
