SMITHSONIAN 



CONTRIBUTIONS TO KNOWLEDGE. 



VOL. XXVIII. 



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v\ 



EVERY MAV Is A VALUABLE MEMBER UP s.n'IETY WHO, BY HIS 1>BSERVA TIOSS, RESEARCHES, ANU EXI'ERIME.VIS, PROCURES 



KNOWLEDGE FOR MEN.— SMITHSON. 



CITY OF WASHINGTON: 



rUBLlSUED BY THE SMITHSONIAN INSTITUTION. 



1 s y li . 



