Boyal Microscojpical Society. 157 



like rows of isolated beads than before. The photographs show the 

 appearances attained in this manner. 



Turning now to the Lepidocyrtns scale, I first examined the 

 one kindly sent me by Dr. Pigott. The slide was labelled as pre- 

 pared by Topping, and marked " 1850, slide twenty years old." An 

 accompanying note from Dr. Pigott to Mr. Hogg says : — " The only 

 good scale is at the edge. The finest old-fashioned scales have 

 become exceedingly scarce." Marks on the slide enabled me with- 

 out difficulty to identify this scale, which was of great size, being 

 nearly the x^oth of an inch in length. It was, however, disfigured 

 by two much smaller scales lying transversely beneath it, and 

 by granular debris which obscured a portion. Still, enough of 

 the scale was visible to serve for examination, and on this I had no 

 difficulty in observing a train of phenomena very similar to what I 

 saw on the Begeeria Nigro-maculcda. The beading, however, was 

 considerably smaller, though the scale was larger than any of the 

 Degeeria scales I selected for study. Encouraged by this result, I 

 worked over all the specimens of Lejndocyrtus curvicollis in my 

 possession, including some slides recently received from Mr. E, 

 Wheeler. I was able to develop somewhat similar appearances 

 even in the smallest and most difficult scales. Of course, the smaller 

 the scale the less satisfactory the resemblance to rows of beads ; but 

 varicose ribbing, more or less closely approximating that seen on 

 the Degeeria, could always be coaxed out, and the efiects produced 

 in the Degeeria scales by raising and lowering the objective could 

 always be more or less distinctly obtained. 



It must also be remarked that aUke in the coarsest Degeeria 

 and the finest Lepidocyrtus scale, the beaded or varicose ribbing 

 appeared always to my eye less sharply defined than the exclama- 

 tion markings. And the photographs likewise possess this quahty. 

 The same quahty will be observed in Dr. Maddox's photographs, 

 already alluded to. I am not disposed, however, to regard this cir- 

 cumstance as an expression of anything more than the fact, easily 

 recognized by the eye when monochromatic light is employed, that 

 the exclamation marks exhibit blacker shadows, and hence afford 

 images (whether to the eye or sensitive plate) possessed of greater 

 contrast than I have been able to give to the beaded ribbing by any 

 management I have yet tried. I must also freely admit that in the 

 smaller Lepidocyrtus scales the beaded character of the ribbing 

 becomes more and more indistinct to the eye, until perhaps its 

 existence is assumed rather on the basis of the similarity of the 

 appearances to those presented by the coarser scales, when these are 

 imperfectly seen, than as an actual objective fact. I presume Dr. 

 Pigott also has experienced the same trouble, or he would not 

 lament the difficulty of finding the " finest old-fashioned scales." 



As to the size of the beading in Lepidocyrtus I must regard 



