65 
and by analogy to those of the Palaeozoic Operculata, lias been detected. So 
many specimens have now been examined, upwards of three hundred, that 
had these structures existed some trace must have come under notice. 
6. Rourrelets or Accretion Swellings. — Throughout the Australian 
Tryplasmce the hourrelets do not form an important feature. In T. Lonsdalei 
these swellings were very slight ; in T. vermiformis represented by delicate, 
equal, rounded rings, closely following one another. In T. congregationis 
and T. columnaris they are irregularly developed, and are stronger and more 
projecting than in any of the other species, with the exception of one doubtful 
example (PI. XVII, fig. 6) of T. princeps. In some instances, at any rate, 
these represent the margins or edges of old calicos. I believe this to be the 
case in T. wellingtonensis. 
7 . Radiciform Rrocesses . — These are tubular prolongations of a 
corallite wall, and were used as anchoring filaments, single or in clusters. 
In some the tubular or hollow nature is very apparent (PI. XXII, fig. 10), 
accompanied by a stereoplasmic thickening arranged in concentric layers. 
They have not been observed in all species, particularly the sub-fasciculate 
forms, but in T. princeps are very noticeable, especially towards the bases of 
the corallites, although they do occur at all heights. Radiciform processes 
are also met with in T. wellingtonensis , but sparingly so, both towards the 
bases of the corallites and around the exterior of the calice margins. They 
occupy the same positions in T. liliiformis, but in contradistinction to T. 
wellingtonensis , were well developed, and of considerable length. 
These anchoring stolons are quite as well developed in T. princeps 
and T. liliiformis as they are in the genus Omphyma (e.g., O. subturbinata, 
D’Orb.). If Nicholson’s statement that the rootlets in this genus are simply 
exothecal structures is correct, 1 then a marked difference exists between the 
latter and the radiciform processes of Try plasma, which are, as already 
explained, prolongations of the general visceral cavity of the coral. Specimens 
of O. subturbinata in the Australian Museum collection certainly appear to 
me to possess hollow processes. 
Lindstrom records the interesting fact that radiciform processes 
“distinguish no less than eleven genera of the Cyathophy lUdie.”* He 
explained their formation as follows : — “ The membrane which lined and 
secreted the walls of the calyx then formed small branches, which also 
1 Nicholson — Man. Pal., 3rd Edit., 1889, I, p. 288. 
2 Lipdstrom — Geol. Mag., 1866, HI, p. 358, f.n. 1. 
