itish 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 information on points
connected with the anatomy of the Cirripedia. To Mr. Conrad I am
likewise indebted for information and assistance. Both the celebrated
Professors, Milne Edwards and Mueller, have lent me, from the great
public collections under their charge, specimens which I should not
otherwise have seen. To Professor W. Dunker, of Cassel, I am indebted
for the examination of his whole collection. I have, in a former
publication, expressed my thanks to Professor Steenstrup, but I must be
permitted here to repeat them, for a truly valuable present of a
specimen of the _Anelasma squalicola_ of this work. I will conclude my
thanks to all the above British and foreign naturalists, by stating my
firm conviction, that if a person wants to ascertain how much true
kindness exists amongst the disciples of Natural History, he should
undertake, as I have done, a Monograph on some tribe of animals, and let
his wish for assistance be generally known.

Had it not been for the Ray Society, I know not how the present volume
could have been published; and therefore I beg to return my most sincere
thanks to the Council of this distinguished Institution. To Mr. G. B.
Sowerby, Junr., I am under obligations for the great care he has taken
in making preparatory drawings, and in subsequently engraving them. I
believe naturalists will find that the ten plates here given are
faithful delineations of nature.

In Monographs, it is the usual and excellent custom to give a history of
the subject, but this has been so fully done by Burmeister, in his
'Beitraege zur Naturgeschichte der Rankenfuesser,' and by M. G. Martin St.
Ange, in his 'Memoire sur l'Organisation des Cirripedes,' th