THE 



MONTHLY MICROSCOPICAL JOURNAL. 



MAY 1, 1874. 



I. — Tlie Scales of Lepisma as seen with Befieded and Transmitted 

 Liglit. By John Anthony, M.D., F.R.M.S. 



(Bead he/ore the Royal Microscopical SociETy, April 1, 1874.) 



Plate LIX. (Upper portion). 



Possessing a very fine slide of Lepisma scales, prepared for me 

 some years ago by M. Charles Bourgogue, of Paris, but of which 

 the covering glass was rather thick, I ventured to remove the said 

 cover in order to substitute a thinner, and finding that to this 

 thick covering glass adhered a considerable number of fine scales, I 

 mounted it, reversed, upon an ordinary 3x1 inch glass slide, and 

 took the opportunity of these facilities for making a series of careful 

 observations of the upper and under surfaces of the Lepisma scale, 

 both by reflected and by transmitted light. 



I will venture to describe what I saw, inasmuch as there were 

 appearances of structure on the surface of the scale and in the inter- 

 spaces of the ribs which, so far as I know, have escaped previous 

 examinations, and also present peculiar points of interest in analogy 

 with other dermal tissues of insects ; moreover, affording a compa- 

 ratively diflicult test of the defining powers of our higher modern 

 objectives — those made some years ago certainly failing all but 

 completely to show the appearances I am about to describe. 



In the Lepisma scale, as usually mounted, I take it to be the 

 under surface of the said scale which is nearest to the eye. I recog- 

 nize the conclusions from Beck's experiments on the characters of 

 the ribs, by which I think it is clearly made out that the quasi- 

 parallel ribs must be on the upper surface of the scale only, while 

 the radiating ribs arising from the quill portion of the scale are on 

 the under surface only; and that there is no admixture or inter- 

 weaving of these ribs towards the edge of the scale, but that the 

 apparent " cross hatching " or " watered silk " appearance is produced 

 by inequalities of surface alone — inequalities probably increased by 

 the drying of the scales. 



My attention was principally directed to the outer or upper 

 surface of the Lepisma scales adhering to my reversed covering 

 glass of the Bourgogne preparation ; I examined it carefully, as if 

 it were an opaque object, with direct light and with a variety of 



VOL, XI. Q 



