MULTIPLICITIES AND MALFORMA TIONS 269 



generations of a human family, Be"dart records quadruple 

 polydactylism of hands and feet through three generations of a 

 Perigord family (C. R. Soc. Biol. Paris, gth series, vol. iv. 1892, 

 p. 367). Lucas cites a case of a Spanish family which included 

 forty instances of polydactylism, and Pliny tells of similarly dis- 

 tinguished families in ancient Rome. Hereditary polydactylism 

 is well known in cats. 



(c) Malformations of Parts. There are records showing the 

 hereditary recurrence of abnormalities in dentition, in the eyes, 



FIG. 28. Half-lop rabbit, an abnormal variation, which by artificial 

 selection has become a stable breed. (From Darwin.) 



in the hands (e.g. webbed fingers), in the feet (e.g. club-foot) 

 indeed, in most parts of the body ; but in most cases the 

 likelihood of transmission does not seem to be great. 



(D) Pre-natal Influences resulting in Mutilations, Multipli- 

 cations, etc. Recent embryological experiments have shown 

 incontestably that certain types of monstrosity can be readily 

 induced artificially by subjecting the developing ovum to shak- 

 ings, alterations of temperature, injections of various stuffs, 

 and so on ; and although the experiments relate mainly to birds, 



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