430 On Ceramopora megastoma and Fistulipora minor. 
in all the localities with F%stulipora minor, there is therefore 
no room left for doubt in this case as to the direct identifica- 
tion of the above organism in all its stages with that which 
ultimately becomes F. minor, M‘Coy. 
I may here mention that Ceramopora megastoma, M‘Coy, 
is very abundant in certain of the argillaceous limestone- 
shales in the Lanarkshire coal-field; yet in many localities, 
except in a few instances, the great majority of specimens 
have rarely advanced in growth much beyond the first or 
Ceramopora-stage. Probably this arose from the conditions 
being unfavourable to its fuller growth and development over 
those tracts of the sea-bottom on which much clayey sediment 
was being deposited. On other horizons, where the strata 
are more calcareous, as in some of the limestones, it is found 
in all its stages of growth. I may also further mention that, 
on nearly all the specimens that have their surface well pre- 
served, macule and monticules are present, and occur at inter- 
vals of about 3 lines apart amongst the cells. These macule 
and monticules, so characteristic of the Monticuliporide, are 
present in all the stages of the organism, the maculee in the 
younger and the monticules in the older stage ; but the latter 
are sometimes also seen on specimens in the earlier stage, and 
are sometimes well developed. In stating that #. minor, 
M‘Coy, possesses monticules that rise in stellate elevations 
above the surface I go against Prof. Nicholson, who says, in 
his definition of J%stulipora, M‘Coy (‘Tabulate Corals,’ 
p- 292), that they “never project as stellate elevations above 
the general surface.” I happen, however, to have one or two 
specimens that clearly show them as such. Prof. Nicholson 
also describes F. minor (p. 306) as having “‘ few or no tabule ” 
in the larger corallites. Prof. M‘Coy, on the other hand 
(Pal. Foss. p. 79), says that they “are only about half their 
diameter apart.” So far as well-preserved specimens in my 
collection show, I find that the tabule in the larger tubes 
vary in different specimens, being sometimes less than the 
diameter of the tubes apart, and sometimes much more; but, 
as a rule, they are moderately common, and are not to be con- 
sidered absent or rare. The foregoing observations on this 
organism have been chiefly derived from the study of speci- 
mens In my own cabinet and that of Dr. Hunter, and they 
seem to me to be quite confirmatory of what Dr. Lindstrém 
has already shown to be the case with certain of the Silurian 
Polyzoa. I shall not, however, enter upon a discussion of the 
vexed question as to the zoological position of the organisms 
showing these changes, but only state that, as regards the 
Carboniferous form, one of two things seems certain, viz.:—that 
