in the hot waters of California. 241 
Diatoms in the thermal waters of Central and Southern Europe 
Irants us in expecting large additions to the Icelandic Dia- 
tomaceze from this source alone.” Now it would be of extreme 
interest to ascertain in what way and to what degree the saline 
and hot waters affect species of Diatomacee, as collections 
might be made in fresh water if it occurs near the hot springs. 
Besides, these forms from the saline as well as from the fresh 
waters of the Pacific coast should be very carefully com 
with those found in the immense deposits so common in that 
part of the world; one of which deposits Frémont found on the 
Columbia river, and others have been detected by the State 
Geological Survey of California in that State and elsewhere. 
The origin of these deposits, and all facts connected with them, 
are of especial importance at,the present time. It must, at the 
Same time, be remembered that the fact as to what constitutes 
@ species in the Diatomacee is by no means settled, as less 
really is known of the life history of these minute organisms 
than of almost any other plants. Moreover, in the study of the 
Diatomacez and allied families, the observer has presented to 
m extremely advantageous opportunities of himself 
acquainted with many points inthe phenomena of cell-life in 
simple as well as more complex plants and animals. I therefore 
ask the codperation of every one at all interested in the prose- 
cution of science and the acquisition of knowledge, to the 
furtherance of this branch of study ; and to such as are able 
and willing to collect I will furnish plain printed directions, and 
to all who desiré to pursue this branch of investigation I will 
gladly furnish all the assistance in the shape of information and 
Specimens in my power. ; a 
Am. Jour. Sct.—Srconp Serres, Vot. XLV, No. 134.—Mancu, 1868. 
16 . aioe: 
