PRE FA CE. lx. 



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 



