248 EXPERIMENTAL EVOLUTION LECT. 



ters belonging, not to the progenitors but to their 

 ancestry, near or remote. Many anomalies in organ- 

 isation are but reversions to former ancestral types ; 

 and reversions exist to a less degree in the many 

 cases when a child, for instance, resembles his 

 grandfather or great-grandmother by some marked 

 peculiarity instead of possessing the traits of one of 

 his direct progenitors. 



4. Indirect atavistic Heredity ', or Heredity tliroiigJi 

 Influence. An instance will explain this form. Lord 

 Morton caused a mare to be mated with a quagga ; she 

 gave birth to a striped hybrid. Mated the following 

 year with a thoroughbred, her progeny was again 

 striped, although not hybrid ; and this occurred three 

 following years, although she was but once mated with 

 the Quagga. The influence of the latter and we do 

 not know what we exactly mean by influence in this 

 case had incorporated itself as it were, in the mare's 

 organism so deeply as to make itself felt even three 

 years after. Such cases are met in human marriage. 

 They are, as yet, unexplained, but they are occasion- 

 ally met with, and positively ascertained. 



5. Homochronoiis Heredity. This term applies to 

 cases where psychical or physical peculiarities put in 

 their appearance among the progeny, at the age when 

 they appeared among the progenitors. Many patho- 

 logical tendencies are transmitted after this mode, in 



