ERRATA. 



Page 67, note 1,/or " Zimmerman" read " Zimmermann." 



„ 70, line 5 from foot, for " developement " read " development." 

 „ 102, last line, /or "fig. 18" read "fig. 20". 

 „ 135, note 1, for " 1889 " read " 1888." 

 „ 136, line 2, for " rasor " read " razor." 



