PREFACE. ix. 



Olive Colored, and Red Algae, are grouped in the 

 ascending natural order, in the text, the orders and 

 genera in each of them are arranged and treated in 

 exactly the opposite order, the first being the most 

 highly, and the last the most simply, organized genus 

 in each sub-class. 



I must take this occasion to express my large 

 indebtedness to several fellow students of Algae, for 

 help in making ready the material for this book. 

 To the published notes, the private correspondence, 

 and personal assistance of Dr. Wm. G. Farlow of 

 Harvard University, I am under very many obliga- 

 tions. I can only regret, for my readers' and my 

 book's sake, that I could not avail myself of all the 

 new knowledge contained in his Manual of New 

 England Algae, which is now long overdue from the 

 Government Press. 



Prof. Daniel C. Eaton, of Yale College, has been 

 ever kind, obliging, and painstaking, allowing me to 

 draw without stint upon his ample store of know- 

 ledge, and his well-furnished herbarium. 



Mr. Frank S. Collins, of Maiden, whose acquaintance 

 with the marine flora of Massachusetts Bay is both 



