152 
NOTES AND MEMORANDA. 
subsists between the sponges and the extensive group of independent 
collar-bearing Flagellate Protozoa, is discussed at. some length ; and 
while recommending these organisms to the attention of working 
microscopists, it is pointed out that it is much to be desired that they 
should supplement their observations by a practical examination of 
the structure of all such sponge forms in the living state to which 
they may have access. In either field our knowledge may be said as yet 
to extend no farther than the threshold, and in each of the same there 
is probably more original discovery waiting to be achieved than in 
any other group of the organic world. 
Mr. Kent gives the following hints as to finding these interesting 
forms. Either salt or fresh water will be found to yield its quota ; 
those frequenting the last-named element being usually the more 
accessible, will most probably command first notice. The investi- 
gator should procure from the nearest weedy ditch or pond a bottleful 
of the finely divided leaves of Myriophyllum, or of tangled confer- 
void growths, in either case selecting more especially those brown- 
hued specimens coloured by a dense incrustation of other more 
minute vegetable and animal parasitic growths. Care should be 
taken to enclose with the water as large a number as possible of the 
specimens of Cyclops and other Entomostraca, to which will frequently 
be found attached species rarely, if ever, to be met with elsewhere. 
Patiently exploring every filamentous division of the weeds with a 
power of 900 diameters, it will be scarcely possible to miss en- 
countering one or more of the species, which with so low a power will 
appear as mere luminous specks, and will require a power of 2000 
diameters for their proper identification. 
The Royal Microscopical Society of the Sandwich Islands. — King 
Kalakua has recently established in his dominions a Society under 
the above title ; particulars of its constitution and operations are on 
their way to this country. The king has always given active encou- 
ragement to science, and in his honour a new fungus, lately discovered 
growing on a boat thrown up on the beach near Honolulu, has been 
named (by Mr. J. P. Moore, of San Francisco) Polyporus Kalakua. 
Count Castracane on Diatoms. — At a sitting of the Botanical 
Society of France last summer. Count Castracane exhibited more than 
2000 photographs of diatoms maguified 535 diameters, and stated 
that his entire collection contained about 3000, of which the nega- 
tives were carefully preserved. He described his mode of ascertaining 
the number of striae in a given space. He projects the image of a 
millimetre divided into 100 parts, so that the enlargement of each 
of the millimetre occupies a space on paper of 18 centimetres. 
“ Taking,” he says, “ a power of this measure, I superpose an image 
of the diatom, selecting the clearest part, and then determine with 
certainty and without fatigue the number of strias that correspond 
with the space of y^^ inch.” 
His measurements led him to deny that Navicula crassinervis, 
N. rhomhoidea Ehr., and Frustulia Saxonica Kaben., belong to the 
same species. He exclaims, “ How could I believe this, when 1 am 
assured that in N. rhomhoidea Ehr. the longitudinal divisions, or, 
more correctly, the intervals between its rows of granules in the 
