HALF-AN-HOUR AT THE MICROSCOPE. 41 



large as the cover ; then cut two small openings in opposite sides 

 of the ring, gum the top of the cell and place the prepared cover 

 on the gummed surface. When dry apply benzine to one of the 

 small ' sluice gates,' and then balsam as before. Put the slide in 

 a warm place for several days, and finish off with white, black, or 

 coloured varnish to fancy. Winter is the best time for dry mounts, 

 as the breath dries off too soon in hot weather ; and summer is 

 the best time for the balsam mounts, as it is difficult in the winter 

 to keep the breath from moistening the isinglass at the wrong time. 

 The cement-cells should be quite dry and hard before mounting, 

 or a dewiness will appear and ruin the object. Soften the cement 

 over the lamp, press the cover down till it sticks all round, let 

 stand a day or two, and finish off. No doubt the diatoms would 

 be more secure if burnt on the cover in the dry mounts, and 

 possibly that process would be sufficient for the balsam mounts 

 without the film of isinglass, as stated on p. 68 of Davies' 

 Manual of Mounting." 



fl^alf^'an^lbour at tbe fiDicroacope, 

 Mttb /IDr. UnUcn meet, f.%.S., f.lR.flX^.^., etc. 



ON receiving a box of slides, the first thing I do is to arrange 

 the slides in order, and I strongly recommend this as a 

 valuable aid to the methodical classification of facts in 

 the mind. 



The FoRAMiNiFERA claim the first place. The Diptera are 

 placed by Westwood lowest amongst the Insects ; Antennae, as 

 outward organs, precede the stomach as an internal one. Fleas 

 are considered to unite this order with Hemiptera (Bugs, etc.); 

 Hymenoptera (Wasps, Saw-flies, etc.), being more highly organ- 

 ised, will follow on. lU/i Mites may be taken to stand lower in the 

 scale than the active, highly-organised Gamasi. 



On Polystomella crispa (PI. 21, Figs, i, 2, 3), Prof. 



Williamson says : — " This exquisite species appears to have 

 attracted the attention of a larger number of Conchologists than 

 any other of the Foraminijera ; a circumstance not surprising 



