VI

rUEFACE.

To Mr. Jenner, one of the most untiring and successfulof Cryptogamic botanists,, and whose excellent Flora ofTunbridge Wells is I believe the only one which containsany thing like a complete list of the freshwater Alga, I amlikewise greatly indebted for numberless recent specimens ofAlgce, which otherwise I had never seen, as well as for manyoriginal and accurate remarks.

To Dr. G. J. Allman, my highly valued friend, and thetalented Professor of Botany in the Dublin University; toDr. Johnston, of whose valuable instructions in zoophy-tology I entertain a grateful remembrance, and to be thepupil of such a master any man might be proud; to MM.Montaigne , Areschoug, Decaisne, and Mr. Shuttleworth,whose residence in foreign lands precluded unfortunatelyfrequent communication, and from whom therefore I regretthat I have not been able to obtain more of that informationof which they are so largely possessed; to Mr. Thwaites,of Bristol, Mr. Sidebotham, of Manchester, Dr. Dickie, ofAberdeen, Mr. M'Colla, of Ireland , and Mr. Thompson, ofBelfast , my warmest thanks are due.

I must not foi’get also to acknowledge the literary assist-ance which I have derived from Mr. Coppin, of TrinityCollege, Cambridge , nor omit to mention the deep obliga-tion I am under to a lady for the devotion of much time tothe shading of many of the plates.

To Mr. Boss, the eminent optician, with one of whose in-struments most of the nicer observations were made, myacknowledgments are likewise due.

To the Subscribers also to this work I feel much indebted;their generous patronage has relieved my mind of consider-able anxiety, for it has removed all pecuniary risk to myself,if it has not insured a reward of the same nature.

Norland Villa, Addison Hoad North, Notting Hill.

Jtdy, 1845.