MEMORANDA. 65 
therefore constitute an indispensable part of a very scientific 
collection of Diatoms. 
We understand that the specimens will be carefully pre- 
pared dry or in balsam, and mounted on thin slides of the 
usual dimensions used in this country (3” x 1”); and to each 
specimen will be affixed a label with the original name, 
locality, &c., whilst a separate list of synonyms, with critical 
notes, will be published with Part V. 
It is hoped that the First Part of each series will appear in 
the early part of, and that the entire publication may be 
concluded within the year. 
The number of collections belonging to the first mentioned 
series will necessarily be extremely limited; but it is to be 
_hoped that the London Microscopic Society will be the de- 
pository of one of them. Those of the second series would 
appear to be almost indispensable for all real students of the 
Diatomacez, and we can only wish that M. Eulenstein may 
find that the pains and trouble he has bestowed upon the 
formation and dissemination of these collections may be 
properly appreciated. 
We have been given to understand that besides Mr. 
Pritchard, Dr. L. Beale and Mr. Roper will be ready to 
afford any further information respecting M. Eulenstein’s 
undertaking that may be required. 
{Prospectuses may be obtained, and the Collections ordered, 
at Messrs. R. and J. Becx’s, 31, Cornhill, E.C.] 
VII.—NEW SER. E 
