ERRATA. 



Ill page 123, line 14 from bottom, omit " not." 



In page 182, after ^' Cheilostomnta,''' pp. 8, 9, add p. 10. 



After "Synoptical Classification of,"/w p. 12, read p. 13. 



The initials S. W. indicate Mr. Searles WooA, 

 and J. S. B., Dr. J. S. Bowerbank. 



