230 THE MICROSCOPE 



EXPLANATION OF PLATES XXIIL, XXIY., XXV. 



Plate XXJII. 



Fig. 1. — Section of Hahenarla chlorantha. a, a, anther ; d, d, viscid 

 disc ; s, stigma ; n, nectary ; n', orifice of nectary ; I, 

 labellum. 



2. — Pollinium viewed laterally. 2^» pollen-masses ; c, caudicle ; 

 d, viscid disc. 



3. — Head of Moth, with two pollinia affixed to the eyes. 



4. — Ditto, one minute after extraction. 



5. — Pencil with two pollinia, one upright (just extracted), the 

 other as it appears one minute after extraction. 



J) 

 >» 



>5 



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J) 



Plate XXIV. 



,, 6. — Section of Orchis mascula. a, anther ; r, rostellum ; s, 

 stigma ; Z, labellum ; n, nectary. 



J, 7- — Pollinium of same, showing, p, pollen-masses ; c, caudicle ; 

 d, viscid disc. 



8. — Front view of discs, d; and caudicles, c; both pollinia being 

 within the rostellum, r. 



9. — Front view of section of 0. mascula. a, anther ; r, ros- 

 tellum ; s, stigma ; I, labellum ; ii, nectary. 



10. — Packet of pollen of Habenaria attached by minute threads, 

 highly magnified. 



Plate XXV. 

 , 11, — Ophrys apifera. p,!^, pollinia ; I, labellum. 

 , 12. — Front view of Ophryii muscifera. a, anther ; r, r, rostellum ; 



s, stigma ; Z, labellum. 

 , 13. — Pollinium of Ophrys muscifera. p, pollen-masses ; c, 

 caudicle ; d, viscid disc. 



Drawn by Mrs. Wheatcroft. 



Z\)c flDicro6cope an& Ibow to ITlec it 



By V. A. Latham, F.M.S. 

 Part VIIL 



B. — Agents which Harden and at the same time 



Colour the Tissues. 



Osmic Acid. — One per cent, solution in water, which can be 

 diluted at pleasure. The solution must be kept in a well-stoppered 

 and dark-coloured glass bottle. It stains fat globules black, and 



