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may occur iu T. Lonsclalei, although I have not clearly seen the former. 
Nicholson says that in some cases compound calicular gemmation gives rise 
to fasciculate colonies, 1 and cites the Silurian Cycithophyllum articulation, 
Wahl., 2 as a case in point. “This peculiarity,” he says, “is partly due to 
the fact that the secondary corallites remain cylindrical, without expanding 
materially ; that they rise side by side without uniting, and without greatly 
diverging ; and that their vertical growth is continued for a considerable 
period before they in turn give rise to calicine buds. Another cause for 
their fasciculate form is, however, to be found in the fact that in these cases 
true parietal gemmation is often combined with true calicinal budding.” 
The relation of T. Lonsclalei to T. vermiformis and T. delicalula is 
referred to in the descriptions of the latter species. Although T. (?) Murrayi, 
mihi., 3 appears to be sub-fasciculate, the more intimate form of growth and 
that of the individual corallites is different. Of the four species described by 
Dybowski, only one ( T . tubulus) is said to be fasciculate, and there are 
fistuhe also, but the septa in the two species differ widely. 
Micro. Structure. — There is a thin proper wall, or tlieca, of dense 
structure presented either as a light or dark ring, usually the latter, followed 
by a moderate thickening of wavy, concentric stereoplasma ; the structure 
of the fistulae is precisely similar. The concentric laminae of the thickened 
septal spines assume a cone-in-cone appearance. Thin sections also reveal 
another very interesting point in connection with these spines, viz., every 
here and there one or more sharp lateral denticles are seen to extend from 
the spines. These are very irregularly developed, as the transverse sections 
of some corallites exhibit none, whilst in others several spines are so provided. 
Another equally interesting point is that the mouths, or entrances into the 
fistuhe, are septal-spinose, and in one instance spines may be seen (PI. XXVI, 
fig. 7) entering the tube itself. On the other hand, the tabulae do not bear 
longitudinal spines as in T. columnaris, & c. It is not often possible, in one 
and the same section, to illustrate both the lamellar and spinose portions of 
a septum; in one section (PI. XXVI, fig. 6), however, such is the case. On 
one side the corallite will be seen the more or less perfect organs, and on 
the other a series of rounded prominences which, I believe, represent the 
lamellar portions only. 
1 Nicholson — Trans. R. Soc. Editib., XXVII, p. 210. 
2 See H. Milne -Edwards and Haime — Mon. Brit. Foss. Corals, Pt. 5, 1854, t. 67, f. 1. 
3 Etheridge — Greol. Surrey Viet. Progress Kept,, No. XI, 1809, p. 32, t. A., f. 1-3. 
Gr 
