vill PREFACE. 
and study, an increased library, an extended knowledge of 
the papers on fossil Bryozoa, and a great addition of fossil 
material, besides the settlement of the question as to what 
the true Bryozoa include. 
With the great variety of opinions on much connected 
with this subject of synonymy, it would be impossible to 
adopt that of all writers, but the lines I have worked upon 
are those of Mr. Hincks and Mr. Waters, for recent and 
fossil respectively, venturing to differ from these known 
authorities only on rare occasions. 
There will be found in this Catalogue a few species of 
which I could not trace the references, not even with the 
help most kindly and unstintingly given me by Mr. Kirk- 
patrick, of the British Museum, to whom I would here 
offer my thanks for all his assistance. Such are the 
‘Bugula Smittit’? of Sars, the ‘ Salicornaria gracilis’ of 
Costa, and two or three more. 
I am painfully censcious of the faults that accompany 
tnis Catalogue, and it is with the utmost diffidence that I 
offer it for the use of students. It has been the occupation 
of several years of ill-health, and to delay publication for 
the advantage of further revision would probably result in 
no publication at all. During this year alone it has been 
entirely laid aside for four months in consequence of iil- 
health. All that I can urge is, that it is an attempt which, 
thus far, has never been made, and I offer it as a stppzng- 
stone to the next student who will undertake a similar 
work. To render a Catalogue of this description perfect 
would require an examination of all the type specimens 
in museums and private collections everywhere, a thing 
which is all very well in theory but impossible in practice. 
To Mr. Hincks for help in references, and to Mr. Deby, 
of London, for the loan of some rarer books and papers, 
my thanks are here tendered. 
