Wenham on Binocular Vision. 
13 
In conclusion I must express my thanks to Messrs. Smith 
and Beck for the prompt assistance that they have afforded 
me in the construction of the instrument, and also for tlie 
free use of such apparatus, selected from their stock, as might 
be useful to me in conducting my experiments. 
A Short Description of some New Forms of Diatomace^ from 
Port Natal. By Geo. Shadbolt. (Read May 25, 1853.) 
The constantly increasing interest evinced in the examination 
of the elegant forms of the Diatomaceae has recently received 
an additional impetus from Messrs. Smith and Beck's publi- 
cation of the first volume of the long expected ' Synopsis of 
the British Species,' by the Rev. W. Smith, F.L.S. 
A work of the kind alluded to will supply a want that has 
been much felt by microscopists, both as a record of what 
has already been accomplished in this branch of study, and 
also as a foundation for a general system of classification and 
nomenclature, for not Only is the latter in the most deplorable 
state of confusion, but by far the greater number of the foreign 
species are only capable of being referred to by their " local 
habitation," being destitute of the other appendage generally 
considered so necessary. 
Under these circumstances I propose conferring a provi- 
sional name on such new species as I am about to describe, 
trusting to the indulgence of any prior claimant to this right, 
whom 1 may unintentionally supplant, and promising to with- 
draw such name on cause being shown. 
About twelve or fifteen months back I was supplied, by the 
kindness of Mr. Geo. Busk, with a gathering of Diatomaceae 
from " Port Natal " so rich that I shall not attempt to give a 
detailed account of the forms already known, but, merely 
noticing a few of the most prominent of these, describe more 
particularly those species that are, so far as I am aware, 
entirely new, endeavouring by the respective designations to 
recall them to the mind, by fixing upon some prominent 
peculiarity of appearance in each as the foundation for such 
distinction. 
From the prevalence of certain forms (although I am not at 
all acquainted with the facts of the case) I should be inclined 
to pronounce the locality whence they are derived as subject 
to marine influence^ and at the same time probably not far 
from the mouth of some river, and it is also evident that the 
specimens are undoubtedly recent. 
Mixed with the Diatomem are some other bodies, which 
are scarcely capable of being classed with them, although, like 
