. } LIBRARY 
NEW YORK 
BOTANICAL 
GARDEN, 
NOTES ON SOME AMERICAN DIATOMACES. 
The present communication contains brief notices of some of the rarer and 
hitherto undescribed species of Diatomacee of the United States Sea Board, 
which have fallen under my observation during the last three years, together 
with a list of a few of the more characteristic and generally distributed coastal 
species. 
The forms to be described are mostly salt-water or brackish. A few species, 
however, known as fresh-water will be noticed where these have been found 
domesticated along with the marine. 
_ I have endeavored, as far as possible, to avoid describing species unless from 
-perfect specimens; carefully rejecting all doubtful and imperfect forms. 
- Sources of error arising from the great variation in size, outline, and striation, 
and from the absence of certain and positive indications whereby the sporan- 
gial may be detected and classified with its typical variety, I have also en- 
deavored to guard against. The want, however, of several important consult- 
ing authorities on this branch in the Academy’s Library, together with the 
not always satisfactory character of the material furnishing the data of this 
paper, often consisting of muds and mixed gatherings, must be my excuse for 
any errors or inadvertencies which may be found in its pages. 
Among those to be described will be introduced one or two doubtful forms, 
probably sporangial, as Amphiprora pulchra Sailey, and extraordinary 
varieties of Surirella o vata and Triceratium alternans, bothof which last 
are figured. 
It is proposed to consider the species to be noticed in the following order: 
1. ‘‘ New species and sporangial forms.’’ 2. ‘‘ Rare species and species not 
hitherto noted as belonging to this country.’? 3. ‘‘ Species characteristic of the 
American coast.’”? 4. ‘‘ Species of universal distribution.”’ 
The precise locality and nature of the gathering from which specimens have 
been derived will be indicated, excepting where species are of general distribu- 
tion and very abundant along the coast, along with such other distinctive 
characters as may be necessary for the definition of new or doubtful species ; 
and as it is not intended that the summary shall present a complete resumé 
of native marine species, mention of many forms known to me not referable 
to one or other of the above four divisions will be omitted. 
It may not here be out of place to add, that the result of my limited investi- 
gations convinces me that a rich and unexplored field lies open in the United 
States for those whose time and attention may hereafter be directed to this 
branch of microscopic research, a branch, until very recently, comparatively 
neglected in this country. Perhaps a reason for this neglect may be found in 
’ the great interest attaching to the less laborious study of the numerous /ossil 
diatomaceous deposits of our country, and of the new and ever varying guanos 
Sp frequently finding their way to our shores. Without any intention of un- 
C@ervaluing the importance of researches on fossil botany, it may yet be doubted 
hether results so satisfactory and important to science are likely to accrue, 
as when the living forms are the subject of study. Nothing certainly would 
seem so well calculated to dampen the ardor of physiological inquiry as pro- 
'Ponged and laborious examinations of the minute detail of the silicious skele- 
ca of these organisms without reference had to the kind and manner of life 
_ =they once invested. 
r — As an additional argument in favor of the study of living species it may here 
e mentioned that many of the fossil forms are still to be found as /iving spe- 
