43 
[dissepimental tissue] at every period of growth.” Lonsdale further added 
that the “ diaphragms” [tabulae] were simply continued between, and possibly 
through, the “ lamellae ” [septal lamellae] to the outer wall, the extension of 
the lamellae inwards being limited. That is to say, Lonsdale conceived a 
Bmgose coral, in which the septa were pierced by pores running trans- 
versely through their substance, the pores in question terminating on the inner 
face edges of these lamellae in short tubuli. Had Lonsdale grasped the 
fact that he was examining a mould, or natural intaglio, instead of a natural 
cameo, he would not have fallen into the error he did, through a misreading 
of the structural details before him, which, when viewed in this light, are of 
actual generic value. 
Some years ago, when describing the first Australian species of 
Try plasma, I offered an explanation of the apparent discrepancy in Lonsdale’s 
specimens. 1 2 The “pores” are not only visible on entirely or partially 
decorticated specimens, i.e., on those in which the proper Avail and septal zone 
are wholly or in part removed, but also on internal casts, pure and simple. 
Now, bearing in mind that the septal apparatus consists, first, of narrow, 
vertical lamellae, and secondly, of free spines protruding inwards from the 
free edges of the latter, it naturally follows that on disintegration or partial 
disintegration of these tissues taking place, grooves running vertically are 
left, bearing at regular intervals pores or small round openings, the grooves 
representing the septal lamellae [lamellae of Lonsdale], the pores his “fora- 
mina,” and their extension inwards his “ tubuli ” ; an examination of many 
of the figures on the accompanying plates will exemplify this far better than 
a lengthy explanation. In other words, Lonsdale did not endeavour to 
reconstruct in his mind’s eye his imperfect specimen of T. cequabilis. Had 
he done so, he would not have afforded Lindstrom an excuse for shelving his 
generic name. 
1852. — In their great work “ Monographic des Polypiers Possiles des 
Terrains Palaeozoiques,” Messrs. II. Milne-Elwards and Jules Ilaime wrote 
of T ry plasma / : — “ If this peculiarity, [the piercing of the septal lamellae by 
pores, &c.] really exists, it will assuredly be quite sufficient to distinguish 
this genus of Cyathophyllidee from all the other forms of the same group ; 
but we are led to believe that Mr. Lonsdale, when he established the division, 
was deceived by an appearance, and u r e have not seen anything similar in one 
1 Etheridge — Kec. Geol. Survey N. S. Wales, 1890, II, Pt. 1, p. 17. 
2 H. Milne-Ed wards and J. Haime — Archiv. Mus. Hist. Nat., 1852, V, p. 393. 
