9 
23 
cluded between the inner boundary line and the innermost 
of the jagged bands, is occupied by two or three rows of 
large, rather linear puncta. Several complete frustules were 
observed, but in that form which the figure was drawn the 
jagged bands, which were nearly complete in the one lobe, 
appeared to have been abraded from the other; the latter was 
marked with nearly parallel rows of puncta. In one case the 
inner margin, when brought more prominently to view, pre- 
sented the outline indicated in fig. 3 0. 
Amphiprora biseriata, n. s., fig. 4.—Valve in front 
view deeply constricted; length °0024, very narrow; striz 
costate. On side view (fig. 4 6) the keel greatly bowed, and 
dipping deeply in the centre. Strize consisting of two nearly 
parallel rows of short coste separated by a blank interspace. 
Amphiprora diadema, n. s., fig. 5.—Valve deeply con- 
stricted in front view; length -0038, its lobes greatly 
rounded, the inner margin rounded, striate, strize costate ; 
strie on lobes costate, fine and waved. All my efforts to 
obtain a front view of this form were ineffectual. 
On an Oren Compressornium. By Joun Barker, M.D. 
(Described at a recent meeting of the Dublin Micro- 
scopical Club.) 
Ir is often a great help to microscopic research to be able 
to apply compression to any object which may present itself 
on a slide while still remaining in the field of view ; and in 
spite of the many and various appliances (very ingenious 
and excellent in their way) most workers prefer to press down 
the cover on slide with the point of a porcupine’s quill, the 
handle of a fine paint-brush, &c., to removing the object 
from the stage and from under view of the observer, and in 
many cases the object is too much crushed, the cover broken, 
or, more likely still, it slips out of the field, and it is often 
impossible to find it again. The compressorium here repre- 
sented will, I think, be found to possess many advantages, 
and its use will get rid of all the difficulties indicated above. 
It consists of two parts, the stage and the compressor. The 
stage (A, B, C, D) is a flat brass plate, with a circular 
opening, bevelled beneath so as to allow any kind of con- 
densor to be applied below, and with two small short pins 
projecting below at a and B (not scen in the diagram), and 
