NOTES AND MEMORANDA. 101 
The collection before us is an effort in the same direction, but is of a 
different kind, and in many respects far more efficient and satisfactory. 
It consists of one hundred slides (the entire collection will probably 
reach five hundred), each containing typical specimens of a species. 
With the exception of a few diatoms, such as Arachnoidiscus Ehren- 
bergu and Aulacodiscus formosus, there are a large number of frustules 
on each slide, and in general there are several genera or species 
present. Thus, on the slide before us, marked Aulacodiscus Oregonus, we 
find several beautiful specimens of a Hyalodiscus. The value of this 
collection, therefore, does not depend upon the mere manual dexterity 
exercised (which is the most remarkable feature of the ‘Typen 
Platte’), but upon the authoritative’ character of the identifications, 
and in respect to this point, we have no hesitation in saying that 
Professor Smith stands at the head of living diatomists. Instead of - 
a single frustule of each species, carefully reduced to its mere 
siliceous elements, we have here a number of frustules; and these, 
although perfectly clean, are mounted as nearly as possible in the 
condition which they presented while living, unless this should render 
them unfit for study. Thus the curious Bacillaria paradoza, instead 
of being mounted as a mere assemblage of striated rods, is put up in 
that singular, connected condition from which it obtains its name. 
From all this it will be seen that these slides are put up to be studied, 
not to be merely looked at. 'They are not intended for those who 
have never seen a diatom; but, on the other hand, to those who have 
even the most elementary knowledge of the subject, they cannot fail 
to prove a reliable and easily followed guide in the determination of 
species. 
ae To gather the material for this collection has been the work of 
many years, and has involved the expenditure of much labour and 
considerable money. The famous collection of De Brebisson has 
been transferred entire to Professor Smith’s laboratory, and has 
furnished many rare species, and it might perhaps be safe to say that, 
in addition to the Professor’s own gatherings, there are few diatomists 
of note that have not furnished him with contributions, either by way 
of exchange or otherwise. 
“The manner in which the collection before us is put up is worthy 
of notice. Each century, or collection of one hundred slides, is 
arranged in five pasteboard trays, each slide having a compartment 
for itself, and the whole being enclosed in a simple but convenient 
pasteboard box. To the lid of this box is pasted a catalogue of the 
Species, which are arranged in alphabetical order and numbered. 
Hach slide is, of course, labelled, and the label is numbered to corre- 
spond with the catalogue. But to prevent any danger of confusion, if 
the slides should accidentally lose their labels by exposure to moisture 
or otherwise, each slide has its proper number written in with a 
diamond, The compartments for receiving the slides are also labelled 
and numbered, thus affording the most perfect security against mis- 
placement.” 
A forth of Collecting Bottle, which appears to be useful, though 
we hardly think novel, is thus described by an American journal :— 
“Tt consists of a bag or net of some light material, to the bottom of 
