ae ee Notes on Diatomacex. 37 
different varieties. As for the two species (G. constrictum and 
capitatum) I have never been satisfied that they are distinct, and 
probably G. hereulaneum is another variety.” 
For my part, from the mode in which the two new valves are 
formed within and between the two old ones, when self-division takes 
place, I can readily understand how a great variation in both out- 
line and sculpture can occur. In this case the two forms have 
exactly the same sculpture, and the difference between them merely 
lies in the outline of the valve. From my knowledge of how 
greatly this character varies in the Diatomacez, I, from an early 
period in my studies, considered these two supposed species to be 
but forms of one, and this discovery proves that my surmises were 
correct. At some future time I may have something to say with 
regard to the genus Gomphonema, and what, in my judgment, 
constitutes a species in it. Iam now engaged, and have been for 
some years, working up several genera, with the express purpose 
of determining the true lines of specific distinction in them. And 
I must be permitted to here enter my earnest protest against the 
custom which has become so wofully common, in England more 
especially, of manufacturing species where they do not exist. 
The labours of such self-supposed students of nature are more 
than thrown away. Our books become crowded with worthless 
synonyms, and this branch of biology has, in consequence, fallen 
into disrepute among scientific observers generally. If those who 
have the opportunity of securing and examining specimens of 
Diatomacez, would only study them a little more carefully, and if 
they must publish, do so only after properly maturing their know- 
ledge, we might hope to learn something of the life history of these 
strange atomies. Better that really new species should for ever 
remain unnamed, than that such contributions to the literature of 
the Diatomacez, as appear from time to time in foreign journals, 
should ever see the light. It is a curious fact that almost everyone 
who becomes possessed of a microscope of sufficiently high magni- 
fying power, at once imagines that he is abundantly armed and 
equipped, as well as qualified, to attack and overcome the most 
difficult problems in biology. Hence we find the most startling 
discoveries put forth by very immature observers of nature, who 
suppose themselves to be students, but who have really given little 
time or thought to study. No branch of biology, perhaps, has 
been more cursed with supposed discoverers of this class than the 
Diatomaceze, until a man comes to be appreciated by the number of 
species he can manufacture. By far the largest number of observers 
who are attracted to these beautiful and wonderful atomies forget 
that we have in them presented to us for investigation one of the 
most puzzling problems in the whole group of phenomena, illus- 
trating that which we call life; but, on the contrary, appear to 
