1900] MICROSCOPICAL JOURNAL. 91 



immediately ready. For microscopic projection the micro- 

 scope is fixed on a sole plate, and brought into use in a mo- 

 ment, or quite as quickly moved aside to allow for the pro- 

 jection of ordinary lantern slides, or opaque objects by in- 

 cident light. The electric light was employed, a special 

 installation having been arranged for the purpose ; but the 

 lantern is also adapted for the limelight and other modes of 

 illumination. The exhibition opened with the projection 

 on the screen of the surfaces of old and new silver coins, 

 a method capable of useful development in rendering visi- 

 ble the chemical changes in metals. Some opaque objects 

 were then shown by reflected light, comprising postcards, 

 diagrams, coin, a watch, and butterflies, set on card, but 

 not otherwise prepared. The lantern was then fitted with 

 the new microplanar lenses, and micro-slides of insects, 

 vegetable tissues, and pathological preparations were 

 thrown on the screen. The great advantages of these len- 

 ses is their high power of definition, all the parts of a pic- 

 ture coming out sharp, the feet of the insects and the ed- 

 ges of the tissues being as well brought out in detail as the 

 body of the one or the central portions of the other. The 

 last part of the exhibition consisted of lantern slides of 

 diatoms, photographs of micro-slides, and some general 

 views. In this part the best was undoubtedly a projected 

 slide of a podura scale, the well-known test used by micros- 

 copists for defining the penetrating power of a lens. 



MICR03C0PK AL NOTES. 



Sportive Habits of Melicerta. — Anyone who has seen 

 this helpless, awkwardly swimming creature when it has 

 had the misfortune to become detached and to be driven 

 out of its tube, will be much interested to hear that it can 

 dart about, in and out of its house, hide behind grains of 

 sand with one eye over the edge or round the corner, and 

 do other frisky gambols with a little preseverance and a 

 grain or two of. imagination. Melicerta can be seen to use 

 its foot as a prehensile organ, in fact, like an elephant his 

 nasal trunk. When a small rotifer of the genus Rattulus 



