VI 
PREFACE. 
tion to this effect was received by Professor Baird, and the opportunity 
afforded me by Mr. Agassiz (to be mentioned below), determined me to 
undertake the task. 
The usefulness of such a work need not be explained to the profes- 
sional naturalist. To every one the nomenclator and index of Agassiz, 
so admirable in its execution, is a vade-mecum. The notorious inac- 
curacy and incompleteness of MarschalPs supplement to it on the other 
hand, and the fact known to me both by personal study and by com- 
munications of others, that several important works had altogether 
escaped notice in any lists, determined me to make the new universal 
index more complete and satisfactory by prefixing to it, in a single 
alphabet, a supplemental list of names which had been omitted from or 
incorrectly given in any of the previously published lists, so that they 
could afterward be included in the general index. 
Confident, moreover, of the support I should receive from naturalists, 
and appreciating the added value which authoritative statements from 
first sources would have, a short notice of my project was published in 
Nature,* and a circular was also prepared and widely distributed, in- 
viting naturalists to send me lists of the genera founded by them in 
recent years, to be included, over their names, in the proposed supple- 
mental list. 
The responses to this appeal were so general, that I soon found the 
task tenfold greater than I had anticipated, and although the work was 
thereby rendered far more satisfactory, it involved so much more labor 
that it would never have been attempted, if foreseen. This, however,, 
lias not deterred me from prosecuting it with the same care that would 
have been given to a less arduous undertaking, although it has been at 
a great sacrifice of time and strength. Not a few persons sent me com- 
plete lists of their genera, including very many already reported, but 
which I was unwilling to omit, from the value which attached to them 
as furnished by the authors themselves. Early in my work I learned, 
that a somewhat similar undertaking had been planned by some of the 
staff of the British Museum, and I would gladly have left it to them 
had not steps been taken which pledged both the Smithsonian Institu- 
tion and myself to the task ; and with great generosity the material 
which had been collected by Mr. Waterhouse was placed in my hands. 
How largely my list has profited by this courtesy, its own pages will 
show. 
It is a special pleasure to acknowledge my indebtedness to Mr. Alex- 
ander Agassiz, who freely placed at my disposal the manuscript addi- 
tions and corrections which Professor Agassiz had made to his Nomen- 
clator. These furnished the most considerable additions to my list, and 
are particularly full in radiates, mollusks, and fishes. t They had been 
collected under the direction of Professor Agassiz, during a long period of 
* Vol. 20, p. 551, October 9, 1879. 
t By an oversight, the principal additions to the lepidoptera, coleoptera and neu- 
roptera were not received. 
