450 



Mr. Scourfield said it had been used in America for a variety 

 of other purposes, and had been found very useful in ascertaining 

 the quantity of organisms contained in water from various depths. 

 It had also been used at the fresh-water biological station in 

 ""llinois for a similar purpose ; and it had been of service in 

 estimating the quantity of food for fishes contained in waters. 



Mr. Karop said that a cheaper, but of course inferior, apparatus 

 for the same purpose could be made with a weighted test tube 

 and a piece of string — the string being tied to the neck of the 

 tube and then whirled round. Where the particles were large 

 this would be found perfectly efficient. 



Mr. Vezey said it had been suggested to rotate the apparatus 

 by electricity — if this were done no doubt the cost would be 

 reduced, as the mechanism would then be very much simplified. 



Mr. Scourfield read a paper " On the Logarithmic plotting of 

 certain Biological data " — a diagram drawn upon the board being 

 used in illustration. 



Mr. Rheinberg read a paper " On a New Modification of Double- 

 Colour Illumination." 



Mr. Goodwin inquired if both the colour discs were in the 

 same plane. 



Mr. Rheinberg said that was so, and that by moving the 

 iris diaphragm any modification of the two colours could be 

 obtained. 



Mr. R. T. Lewis read a " Note on Peripatus Moseleyi" 

 compiled from communications received from the Rev. J. R. 

 Ward, of Richmond, Natal. A specimen in a tube of glycerine, 

 and a coloured drawing of the animal, were exhibited in illus- 

 tration. 



Mr. Ingpen hoped it might be possible to obtain some mounted 

 portions or dissections of this creature for exhibition under the 

 microscope, as they would be very valuable and interesting. He 

 had been reading the section of the " Cambridge Natural History " 

 referred to, and had found it exceedingly interesting. 



Mr. Lewis said he had some hope of receiving some mounted 

 specimens of the veiy young individuals, and he had also the 

 promise of some examples of the New Zealand species. These 

 had, however, not yet come to hand, but if they were received 

 1 iter on he should be very pleased to bring them up to one of 

 the meetings for exhibition. 



