MEMORANDA. 243 



Diatomaceae, on account of the great difficulty I have hitherto 

 experienced in procuring slides free from mud, sand, and 

 other extraneous matters. — H. Munro, M.D., M.R.C.S., &c., 

 Hull 



Campyiodiscus cirpeus. — On September 6, I found in brackish 

 water, near Yarmouth, what I took to be Campylodiscus bicos- 

 tatus, specimens of which so named I distributed amongst 

 several members of the British Association, at the Liverpool 

 meeting. I now find it should have been named C. clypeus, 

 and which I understand is new to Britain. — R. Wigham, 

 Norwich. 



Cilia on the surface of Conferrse. — Although I am aware that 

 the existence of cilia on the Oscillatorice has been inferred 

 from the motion of particles of matter in the water in their 

 neighbourhood, I am not certain whether any observer has 

 distinctly seen them. It may be of interest to some of your 

 readers to know that by using a dark stop with the achro- 

 matic condenser, the whole surface of a large species of 

 Oscillatoria (found in brackish water) may be seen covered 

 with cilia moving in a circular sweeping wave round the 

 axis of the organism : this motion is particularly distinct 

 and beautiful at the sutures of the segments, where the 

 cilia may be seen en irrqfile, and seem to form a distinct 

 fringe. At the "smaller end," which one occasionally finds 

 on the longer pieces, the motion is very lively, as well as that 

 peculiar " vermicular" waving which is so characteristic of the 

 species. The ciliary movements are only to be made out 

 clearly (in the specimens which I have examined) whilst they 

 are in a state of progression, which inclines me to suppose that 

 that motion at least is produced by their agency. 



The object-glass used was a l-4th, of Mr. Pillischer's make, 

 with a large angle of aperture, and the shallow eye-piece. — 

 G. H. KiNGSLEY, M.D., Glossop Hall, Derbyshire. 



On an easy method of vriping Thin Olass Covers. — As many of 



the readers of the 'Microscopical Journal,' like myself, may 

 have found great difficulty in wiping the thin glass covers for 

 microscopic objects, by the ordinary method of holding them 

 betVeen the thumb and finger, without occupying considerable 

 time and frequently breaking them ; may I venture to suggest 

 that the following method, which I have adopted for some time, 

 will, I think, be found a much easier, and at the same time 

 a much safer way of effecting the above object? 



After having washed the covers, I take two or three out of 



R 2 



