1170 Proceedings of Royal Society of Edinburgh. [sess. 
Among the interesting reactions discovered by Dr Marshall may 
be mentioned the ready solubility of metals, such as copper and 
silver, without evolution of gas, in solutions of persulphates, an action 
which has found an application in photography ; also the action 
of silver salts on solution of ammonium persulphate, in which 
ammonia is directly oxidised to nitric acid at the ordinary 
temperature. The oxidising action of persulphates has also been 
made use of in the preparation of some artificial dye-stuffs and in 
bleaching. 
The Makdougall-Brisbane Prize for 1900-1902 was presented 
to Dr Arthur T. Masterman for his paper entitled “ The Early 
Development of Cribrella ocidata (Forbes), with remarks on 
Ecliinoderm Development,” printed in Yol. XL. of the Trans- 
actions of the Society. 
The Chairman, on presenting the prize, said : — 
The observations given in Dr Masterman’s paper provide many 
new data for the discussion of the vexed question of the hom- 
ologies of the various coelomic cavities present in Echinoderms. 
Briefly his observations on the development of Cribrella oculata 
may be summed up as follows : — At the close of segmentation of 
the egg a solid morula of cells is produced, from which a 
blastula is formed by a process peculiar to Cribrella , which Dr 
Masterman has termed egression. Gastrulation follows, and later 
the archenteron divides into mesenteron, anterior coelom and 
posterior coelom. The anterior coelom becomes sub-divided into 
four portions — the hydrocoel, the epigastric coelom, the central 
coelom and the pre-oral coelom — the fate of each of which has 
been carefully traced. One of the most important points in the 
paper is the weight of evidence accumulated to prove the homology 
of the hydrocoel and epigastric coelom as left and right portions of 
the anterior enterocoelomic punches. The central coelom becomes 
the dorsal sac or cardiac vesicle, and the pre-oral coelom remains, 
in fact, as the axial sinus. The right and left posterior coeloms 
fuse to form the hypogastric coelom. In addition to these most 
important observations on the fate of the coelomic cavities, 
Dr Masterman has worked out many other interesting points in 
the development ; he has determined the relation of the planes of 
