Prof. H. A. Nicholson—On the Favositide. 105 
Fleming’s collection. If he had detected mural pores in microscopic 
sections, we would have regarded such as being one of the greatest 
discoveries of modern times. Is it to be expected that such delicate 
pores could retain their normal aspect, surrounded and impregnated 
by induced calcareous matter during fossilisation? Indeed, we have 
failed in detecting the mural pores in the genus Michelinia by the 
microscope, which is of gigantic proportions in comparison to any of the 
four species of Alveolites. In, however, weathered specimens of either 
we find no difficulty in detecting the mural pores, and in no locality 
have we procured better examples showing such than is to be found 
in the examples of A. depressa, found in Charleston Quarry, Fifeshire. 
A variety of Alveolites, which we believe has been rashly relegated 
to the genus Cheates hyperbolus,' by Nicholson and Htheridge, jun.” 
So far as concerns the genus Alveolites, Lam., in particular, it is 
unnecessary to criticise the statements contained in the above note ; 
since the note itself contains the plainest proof that Mr. Thomson 
does not know what the genus Alveolites, Lam., is, and that he is not 
acquainted with any species of the same. The first point is sufficiently 
shown by his assertion that “the type” of the genus is “in Dr. 
Fleming’s collection”; whereas the type of the genus Alveolites, as 
every paleontologist knows, is the familiar A. suborbicularis, Lam., 
of the Devonian rocks, and is preserved at Paris. ‘The second point 
is equally clear from his speaking of “ the four species of Alveolites,” 
as if there were only four species in the genus; the truth being that 
“the four species” to which he refers (viz. Chatetes septosus, Flem., 
C. depressa, Flem., C. capillaris, Phill., and C. Htheridgii, Thoms.) 
belong to the genus Chetetes, Fischer, and are not referable to the 
genus Alveolites, Lam., at all. 
As regards the general question involved, in view of all that has 
been published in recent times as to the minute structure of the 
Favositoid Corals by Ferd. Roemer, Lindstrom, Schliiter, Frech, 
Foord, R. Etheridge, jun., the present writer, and others, it is 
difficult to believe that one who professes to have studied Paleozoic 
Corals should speak of the recognition of mural pores in thin 
sections of Alveolites as still unaccomplished,’ or of its possible 
accomplishment as being “one of the greatest discoveries of modern 
times.” Even in the days of those great masters—Milne Edwards 
and Haime—before the method of working by means of thin sections 
had come into use at all—it was a familiar fact that mural pores could 
readily be recognized in polished slabs of the Favositoid Corals. 
Mr. Thomson does not appear to have grasped the elementary fact 
1 By ‘‘the genus Oheates hyperbolus’’? Mr. Thomson refers, I presume, to the 
“‘species”? described by Mr. R. Etheridge, jun., and myself, under the name of 
Chetetes hyperboreus. 
2 Mr. Thomson’s disbelief in the possibility of recognising mural pores in thin 
sections of the Favositoid Corals is, it may be noted, of comparatively recent growth. 
Thus, in a paper published in the Proceedings of the Philosophical Society of Glasgow 
in 1881, Mr. ‘Thomson described and figured what he believed to be mural pores in 
thin sections of Chetetes Etheridgii, Thoms. sp. A reference to his figure (/oc. cit. 
pl. i. fig. 7) will show, however, that in this case the supposed ‘‘mural pores’’ are 
represented in the centre of the calcite filling the visceral chambers of the corallites, 
and that they are really nothing more than minute granules of calcite. 
