ZOOLOGY AND 1JOTANV, MICROSCOPY, ETC. 



71 



a height of about 17 cm., and can be inclined at any angle up to 35° to 

 the horizontal. The Microscope is screwed on to the ground-plate. 

 Arm supports are provided to rest the draughtsman's hand. 



Reichert's Marking Apparatus.* — This is constructed with a 

 diamond point, and will be easily understood from the illustration (fitr. 

 171). 



6. Miscellaneous. 



Paraffinum liquidum (B.P.) as an Immersion Oil.f — C. Rowntree, 

 after alluding to the drawbacks of cedar-wood oil, points out that 

 paraffinum liquidum (B.P.) is an efficient substitute. It is a colourless 

 and transparent fluid, inexpensive, and keeps in any climate indefinitely. 

 As it is non- volatile, it does not dry up, and is easily wiped off from 

 cover-glasses and objectives. Its index of refraction is somewhat lower 

 than that of cedar-wood oil, but for the ordinary purposes of bistology 

 and bacteriology the optical results are at least as good. Both with 

 apochromatic and achromatic lenses the definition and illumination are 

 excellent, even with a magnification of 1600 diameters. It is especially 

 valuable for the examination of film preparations. 



Quekett Microscopical Club. — The 450th Ordinary Meeting was 

 held on October 2, the President. Professor E. A. Minchin, M.A., F.Z.S., 

 in the chair. Mr. T. A. O'Donoboe exhibited and described some photo- 

 micrographs of Podura scale x 2000, taken with condenser cones of 

 aperture 0*35-0 "65, and expressed the opinion that a small cone gave 

 an altogether wrong impression. Mr. C. P. Rousselet, F.R.M.S., 

 exhibited and described a new species of Rotifer, Notholca bostoniensis 

 sp. n., he obtained in Boston, U.S.A., in August 1907. Mr. I). J. 

 Scourfield, F.Z.S., F.R.M.S., made a few remarks on Entomostraca 

 Mr. Rousselet had brought from Boston, mentioning points of similarity 



* C. Reichert, Vienna, Catalogue, Mikroskope, No. 20 (1908) p. 62, fig. G6. 

 f Journ. Pathol, and Bacteriol., xiii. (190S) p. 28. 



