Minutes of Proceedings. 
xvii 
'* Exhibition of Limnocfiida rhodesiae, Blgr.," by Mr. K. H. Barnard. 
Since the first discovery of a fresh-water jelly-fish under artificial con- 
ditions in London in 1880, several other species have been discovered in 
various parts of the world. Most have been found in Africa — in the 
basins of the Nile, Congo, and Niger. Quite recently Dr. Arnold, of the 
Bulawayo Museum, has discovered a new species in the Zambesi Eiver 
at Livingstone. The species is being investigated by C. L. Boulenger 
and Dr. Arnold. 
Exhibition of specimens showing " Life History of Strongylus 
Douglasi," by Dr. H. Bayon. 
Droppings containing eggs of the helminth causing " vrot magen " in 
ostriches have been kept at room temperature, and show after three 
months numerous living larval stages of the parasite. These were 
described. 
A demonstration was given of the following protozoa : — 
1. Leishmania of oriental sore in living pure culture. 
2. A haemogregarine from the spleen of a sewer rat caught in 
Cape Town. 
3. Cocctdium cuniculi from the liver of a wild rabbit from Eobben 
Island. 
Papers : — 
{a) " Some New South African Aloes/' by J. B. Pole-Evans. 
The paper describes six new Aloes from the Transvaal, viz. : — 
1. Aloe longihracteata, Section Saponariae, Berg. 
2. Aloe Pienaarii, Section Tropicales, Berg. 
3. Aloe Wichensii, Section Tropicales, Berg. 
4. Aloe glohuligenima, Section Pleurostachya, Berg. 
5. Aloe Pretoriensis, Section Arborescentes, Berg. 
6. Aloe aculeata, Section Principales, Berg. 
Of these A. Pienaarii, A. Wichensii, A. globuligemvm, and A. aculeata 
may be regarded as sub-tropical to tropical species. 
{h) " Optical Illusions," by Th. Wassenaar. 
(c) "On a New Genus of Fresh- water Oligochaetes (of uncertain 
position)," by E. J. Goddard and C. S. Grobbelaar. 
{d) '*0n the Space-lattice of Liquid Crystals," by J. S. v. d. Lingen. 
The theory of the identity of molecules which cause the different forms 
of crystals of the same substance was discussed briefly. 
Experiments on the magnetic nature of certain liquid crystals were 
then described. The principal axis of the molecules lies parallel to the 
lines of magnetic force when the molecules are not influenced by other 
forces. 
As regards the optical properties of liquid crystals, the pseudo-isotropic 
layers behave like uniaxial crystals cut perpendicular to the axis. 
