6o6 Church. — The Structure of the Thallus of 
vicinity of the chlorophyll-corpuscles, as soon as formed, 
rather than tend to accumulate first in the cell-sap. Nor is 
the analogy with the case of secondary oxalate formation 
a strict one, since in this case the injurious acid oxalate is 
neutralized inside the cell, and the harmless calcium salt 
excreted. Further, Loew 1 suggests that the observations of 
Klebs and Hassack on the formation of alkaline carbonate 
may be vitiated by peculiar reactions of the colour-test 
employed. It is evident that, in Neomeris , the precipitation 
takes place outside the membrane, and either hypothesis might 
account for its formation, but it may be pointed out that, even 
if precipitation be entirely ascribed to the excretion of an 
alkaline carbonate which still remains hypothetical, the with- 
drawal of carbonic acid from the surrounding medium will 
still play an important part in maintaining the incrustation. 
For, living in shallow water, it is evident that the free carbonic 
acid present in the medium, which tends to decalcify the 
calcareous substratum, would also tend to decalcify the 
incrusted plant ; and it has already been shown that the older 
segments decalcify as their assimilatory activity ceases, and 
before they become finally detached from the main axis. 
1 Flora, 1893, p. 419. 
EXPLANATION OF FIGURES IN PLATES 
XXI, XXII, AND XXIII. 
Illustrating Mr. Church’s paper on Neomeris. 
PLATE XXL 
Fig. 9. Natural size. 
Figs. 7 and 15 Zeiss 3 D., all the others Zeiss 3 A. Figs. 1-8 reduced |. 
Figs. 10-16 reduced f. 
Fig. 1. Young plant of Neomeris dumetosa , bearing apical whorl of 6 members, 
and 2 whorls of 6 scars each,— enlarged view of apex at the side. 
Fig. 2. Well-grown specimen in Stage I. Upper 5 whorls with full appendages. 
