DESCRIPTION OF PLATES. 



The diameters which each object is magnified, are expressed in the Plates by small 

 numbers placed beneath the object. 



PLATE 1. Test-Objects. 



Figure 



1. Hairs of the larva of the so-called Dermestes lardarius, viewed in balsam. 



2. Hairs of the common bat (Vespertilio pipistrellus), in balsam, a, 6, coloured 



hairs ; r, a white hair. 



3. Hairs of mouse (Mus musculus), in balsam. 



4. Pits of coniferous wood, common deal (Abies excelsa), viewed dry. 



5. Mucus- (or salivary) corpuscles, seen under different powers. 



6. Scales of Lepisma saccharine^ dry. 



7. Scale from the wing of Morpho Menelaus, dry. 



8. Scale from underside of wing of common clothes-moth (Tinea pellionella), dry. 



9. Scales of Hipparchia janira. a, dry, and by oblique light; 6, in balsam, by 



direct light; c, dry, after Schacht. 



10. Didymohelix ferruginea, under different powers ; >, with imperfect correction 



or adjustment, c with perfect correction and adjustment ; c, separate fibres. 



11. Didymopriiun Borreri, empty cells. 



12. Scales of Podura (Lepidocyrtus), under different powers, dry ; a, 220 diameters : 



c, portion of scale left hand, three markings as seen when the adjustment 

 of the object-glass is correct and the markings in focus ; right hand, showing 

 the markings dividing when the adjustments are correct and the focus altered 

 the least possible either way. 



13. 'Pygidium of flea. 



14. Frustule of Grammatophora manna (diagram), a, front view ; 6, side view. 



15. Frustule of Grammatophora subtilissima (diagram). a } front view ; 6, side view. 



16. Pleurosigma angulatum ; dry valve showing the dots. 



17. Pteurosigma attenuatum; dry valve showing the lines. 



18. Pleurosigma elongatum ; dry valve showing the lines. 

 1 ( J. Bacillus subtilis. 



20. Bacterium termo. 



