PREFACE. Ml 



finest collection of British species, and their varieties, 

 which I have seen, together with many very valuable 

 MS. observations, and the results of experiments. Prof. 

 Owen procured for me the loan of some very interesting 

 specimens in the College of Surgeons, and has always 

 given me his invaluable advice and opinion, when con- 

 sulted by me. Professor E. Forbes has been, as usual, 

 most kind in obtaining for me specimens and information 

 of all kinds. To the Rev. R. T. Lowe I am indebted for 

 his particularly interesting collection of Cirripedes from 

 the Island of Madeira — a collection offering a singular 

 proof what treasures skill and industry can discover in 

 the most confined locality. The well-known conchologist, 

 Mr. J. G. Jeffreys, has sent for my examination a very 

 fine collection of British specimens, together with a 

 copious MS. list of synonyms, with the authorities 

 quoted. To the kindness of Messrs. M c Andrew, Lovell 

 Reeve, G. Busk, G. B. Sowerby, Sen., D. Sharpe, 

 Bowerbank, Hancock, Adam White, Dr. Baird, Sir John 

 Richardson, and several other gentlemen, I am greatly 

 indebted for specimens and information : to Mr. Hancock 

 I am further indebted for several long and interesting 

 letters on the burrowing of Cirripedes. 



Nor are my obligations confined to British naturalists. 

 Dr. Aug. Gould, of Boston, has most kindly transmitted to 

 me some very interesting specimens ; as has Prof. Agassiz 

 other specimens collected by himself in the Southern 

 States. To Mr. J. D. Dana, I am much indebted for 

 several long letters, containing original and valuable infor- 

 mation on points connected with the anatomy of the 



