ERRATA. 



On page 49, line 15, for &quot;April,&quot; read May. 



On page 122, second line from the bottom, for &quot;30,&quot; read 50. 



On page 168, line 29, for &quot; sin Jf,&quot; read cos I. 



On page 151, lines 6 and 24, for &quot;p. 6,&quot; read/. 150. 



On page 92, line 18, for &quot;Hornett,&quot; read Thornette. 



On page 221, line 14, for &quot;ascending,&quot; read according. 



On page 273, line 13, for &quot;Boscawen,&quot; read Webster. 



On page 332, line 7 from the bottom, for &quot;Gibbon,&quot; read Gliddon. 



On page 379, last line, for &quot;gennanica,&quot; read germanica. 



On page 412, omit &quot;B. lanceolatum,&quot; seventh line from the bottom. 



On page 461, fourth line from the bottom, for &quot;Samarancy,&quot; read Sat/iaraiii. 



On page 505, fifth line, for &quot;Microsterias,&quot; re^&Micrasterias. 



On page 541, line 9, for &quot;Mt. Washington,&quot; read WJiite Mountains. 



On page 414, line n from the bottom, erase &quot;P. oculata.&quot; 



On page 212, line 2, omit &quot;Mt.,&quot; before Wilton. 



