[OCTOBEE, 1901.] 



THE 



SCIENTIFIC TRANSACTIONS 



ROYAL DUBLIN SOCIETY, 



VOLUME VIL— (SERIES 11.) 



XIII. 

 VAEIATION : GEEMINAL AND ENVIEONMENTAL. 



BY 



J. C. EWART, M.D., F.R.S., 

 Eegius Professor of Natural History in the University of Edinburgh. 



DUBLIN: 



PUBLISHED BY THE EOYAL DUBLIN SOCIETY. 



WILLIAMS AND NOEGATE, 



14, HENEIETTA STREET, COVENT GARDEN, LONDON; 



20, SOUTH FREDERICK STREET, EDINBURGH; and 7, BROAD STREET, OXFORD. 



PRINTED AT THE TJNIYERSITY PRESS, BY PONSONEY AND "WELDRICK. 



1901. 



Price One Shilling. 



