ON MOUNTING DIATOMS, ETC. 39 



Fig. 15. — Nerve-centres; g.g., cephalic ganglia. 



Fig. 10. — Sensory cephalic papillae with ganglia. 



Fig. 17. — Distribution of trachece over proventriculus. 



Fig. 18. — Labium or under lip. 



®n fIDouutino Diatoms, ac, in Xiuee anb 

 Ipatterne* 



From "The Journal of the Victoria Microscopical Society." 



MR. H. Sharp gives the following directions for this kind of 

 mounting, his slides thus prepared being said by Mr. W. 

 H. Wooster to be " exquisite examples of manipulative 

 skill " :— 



" Requisites. — (i) One or two cat's or mouse's whiskers fastened 

 on match-like sticks or fine rushes, with shellac rather than gum, 

 with about \ inch free. I prefer to have one with the natural 

 point, and another with the point cut back to where it is somewhat 

 stiffen (2) A good simple Microscope of some kind, either 

 attached to a roomy stage-plate, with a mirror below and revolv- 

 ing-plate above, or detached on some stand, cut capable of being 

 brought over a mounting-table with mirror and rotating plate as 

 above. My own is home-made, extremely simple, costing nothing 

 but the trouble, and such as any one with a little ingenuity could 

 make for himself It consists of a piece of pine 9 inches long, 

 5 inches wide, and i inch thick, on three legs, with a hole in the 

 centre, into which a wooden matchbox (with the bottom cut out) 

 fits tightly, projecting a little above ; over this fits a piece of slate 

 just tight enough to rotate easily ; beneath, a peg receives the 

 mirror of the Microscope. This forms the detached mounting- 

 table. For the simple Microscope, I take the foot and tube-pillar 

 of the condenser, fit a piece of cane in this tube, drive a pickle- 

 bottle cork stiffly on it, and fasten on this a horizontal wooden bar 

 with a hole in the middle to fit on the cane, and another at each 

 end in which to fit the lenses, which are just the ij-inch and 



