XX 
Transactions of the Boyal Society of Soutli Africa. 
distorted forms are not so frequent. The diameter of the rounded forms 
averages 10 microns. 
The chromatin granules are more or less scattered, and the meta- 
chromatin granules, noted in the female form, are absent. 
The nucleus of the host cell is most frequently elongated or irregular 
in shape, and usually situated at the edge of the host cell, and appears, 
in many instances, to be hypertrophied. 
Age of ajfected birds.- — A number of smears from ostriches of various 
age were examined, with the result that the infection was not observed 
in adult ostriches. 
Transmission exim^iment. — So far gave negative results. 
The Leucocytozoon not having been described yet, I propose to call 
it " Leucocytoozon struthionis.'^ 
" Valency and Chemical Affinity," by Dr. Mom. 
Two and a half years ago the author showed that the atomic weights 
could be fairly exactly calculated by making use of a proton, fi, of atomic 
weight, about O'OOQ. The author has now discovered evidence that this 
proton may really be, as was suspected in 1909, the true cause of valency 
and of chemical combination. This evidence consists in the fact that 
practically the same value of /x is given by the three most exact 
determinations of molecular ratios that he is acquainted with. 
Description of a New Species of Trygon {Trygon schreineri) from 
South Africa," by Professor Gilcheist. 
Three species of the Pijl-staart, or Sting Eay (Trygon), have been 
recorded from South African waters. A description of a fourth, which 
seems to be a new species, is now given. 
Ordinary Monthly Meeting. 
June 19, 1912. 
The President, L. Peringuey, was in the Chair. 
The Minutes of the Meeting held on May 15th were confirmed. 
The President announced that the Council had selected W. A. Jolly, 
J. Medley Wood, B. de St. J. van der Eiet, as candidates for Fellow- 
ship. The election will take place at the Annual Meeting on September 18th. 
Nominations : L. Carpenter, W. H. Taylor. 
Elections : A. Devries, J. Burton. 
Communications : — 
"The Eainfall on Table Mountain for Thirty Years," by Mr. T. 
Stewart. 
