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Favosites. By this I do not mean to infer any systematic relation between 
the two groups, but simply a connection in the light of comparative 
morphology. 
A few words on the septal lamellae and spines of the Operculate 
Corals (Calceolidae) will not be out of place. In these corals the septal 
apparatus is incomplete and rudimentary, or even obsolete ; in Goniophyllum 
and Calceola , although marginal, it is truly lamellar ; in Rhizophyllum there 
are septal striae; in Arceopoma, these are again reduced to lines of tubercles. 
On the whole, therefore, the septal characters of Tryplasma do not entirely 
agree with those of the Operculate Corals any more than they do with any 
other group of the Itugosa. 
In the historical portion of this Memoir, I referred at some length to 
the supposed existence of canals traversing the wall, as described by Lonsdale, 
and showed these to be nothing more than cavities left by the removed septal 
spines. In by far the greater number of instances our Tryplasvue are met 
with in the decorticated state — devoid of the theca — which has been worn off 
cither during or subsequent to fossilisation. If this form of disintegration is 
carried sufficiently far to remove the septal lamellae also, one or the other of 
the following conditions is apparent : — a, The remaining portion of the corallite 
is traversed by longitudinal rows of circular dots, which are the fractured 
bases of the septal spines ; b, or by holes instead of dots, leading to short 
tubuli, which are simply moulds left by the dissolved spines. Many beautiful 
examples of these are in our collections, and in the case of the tubuli none 
better need be referred to than the small example of T. derrengullenemis 
(PI. XXII, figs. 6 and 7), in the calice cast of which are several cycles of 
“canals.” In species possessing differentiatedprimary and secondary lamellae, 
the lines of pits will always be found to be larger and smaller alternately. 
12. Loculi. — In consequence of the narrowness of the lamellae septal 
loculi do not exist (even in T. (?) Murrayi), the short interspaces between the 
bases of the lamellae being invariably filled with a secondary deposit, leaving 
the spines only free. 
13. Dissepiments. — The remarks made in the last paragraph naturally 
prepare one for the absence of any endothecal tissue of the nature of 
dissepiments. So far no satisfactory evidence of their presence exists, with 
the sole exception of T. (?) Murrayi , which will be referred to later on ; at any 
rate, certainly not in the subfasciculate species. On first describing T. 
