LIME-FORMING LAYER OF MADREPORARIAN POLYP. 203 
The Lime-forming Layer of the Madreporarian 
; Polyp. 
By 
Maria M. Ogilvie Gordon, D.Sc., Ph.D., F.L.S. 
Havine just received Mr. Duerden’s new and valuable 
work on ‘The Coral Siderastrea Radiauns and its Post-larval 
Development,’ 1 I wish to draw attention to one or two of the 
points in which his work covers the same field of investigation 
as my work on ‘ Madreporarian Types of Corals,’* published 
in 1896. My work in no sense professed to be astudy of the 
histology of Madreporarian corals; it explicitly dealt with the 
coral skeleton, and it set forth, for the first time, the exquis- 
itely fine lamellar structure of the skeletal parts. My micro- 
scopic observations of skeletal structures have been verified 
by many students since the work appeared, but zoologists 
generally have regarded my view that the crystalline deposit 
took origin within organic tissue as quite wrong. Mr. 
Duerden, who approaches this subject from the histological 
standpoint, arrives at results which, in this very important 
feature, corroborate my view. 
Those familiar with the scientific literature of the Madre- 
1 J. E. Duerden, ‘The Coral Siderastrea Radians and its Post-larval 
Development,’ Washington, U.S.A. Published by the Carnegie Institution, 
December, 1904. 
2M. M. Ogilvie, “ Microscopic and Systematic Study of Madreporarian 
Types of Corals.” London, Royal Society ‘Transactions,’ vol. 187 (1896), 
b., pp. 83—349. 
