224 CROSSING AND CLOSE-INTERBREEDING. 



Another rule, which may be observed to obtain, in 

 determining prepotency, is, that, if any given ratio 

 (whether of a positive, or of a negative cast) of the 

 development of the characters, of the species, has 

 been long maintained, either through interbreeding, or 

 through the long-continued, fortuitous mating of indi- 

 viduals similar in development, the product of such a 

 line will generally be prepotent, even when mated with 

 individuals, with characters whose usual effect would 

 be to alter or amend such ratio. 



With respect to the prepotency of sex, adverted to 

 above by Darwin: While such prepotency is fre- 

 quently explicable, upon the above principles, it is 

 also amenable, frequently, to another rule. Many char- 

 acters are correlated, either directly or indirectly, with 

 both primary and secondary sexual characters. Both 

 the sperm, and the germ, undergo, before fecundation 

 occurs, an independent, though very small develop- 

 ment, just appreciable by the microscope. If the con- 

 gression of the two transpires, when the spermatozoon, 

 for instance, has advanced, but little, in its development, 

 and after the ovum has run much or .all of its course 

 of little, independent development, the female element 

 will have, not only the power of impressing its special, 

 sexual coordination upon the foetus, but will often, per- 

 haps, have also the power to influence the development 

 of the characters, common to both sexes, but which are 

 correlated, in some respects, with the female's primary 

 or secondary, sexual parts. As this physiological law 

 is operative, in so many ways which are determined by 

 ' an equal variety of degrees of the respective develop- 



