PREFACE. Vll 



obligations. To my much-esteemed friend, Dr. John Flem- 

 ing, Professor of Natural Science in the New College of 

 Edinburgh, I owe much, not only for what instruction I 

 have derived from his well-known publications, but for in- 

 formation which I have received from his kind correspond- 

 ence, without which I probably should never have entered 

 on this department of study. To Dr. George Johnston, 

 another much-valued friend, I need not say that I am spe- 

 cially indebted, for almost every page of my book proclaims 

 my obligations ; and I hope it may prove a stepping-stone 

 to his admirable volumes. To George Busk, Esq., of 

 Greenwich, I return my grateful thanks, for not only giving 

 me information and drawings, but for kindly superintend- 

 ing the arrangement of the illustrations, and thus contri- 

 buting much to the usefulness of the work. To the Rev. 

 Thomas Hincks, of Exeter, I am truly thankful for favour- 

 ing me with a list of Devonshire Zoophytes, with specimens 

 of the rarest of them, and for kindly permitting me to use 

 his articles in the ^Annals of Natural History' respecting 

 interesting Zoophytes which he has added to the British 



