83 
Locality. — Bank of Yass River, Portion 12G (shale below limestone), 
Parish Yass, County King (R. Etheridge — Australian Museum) : Derren- 
gullen Creek, a branch of the Yass River, Parish Yass, County King ( C . A. 
Siissmilch— Technical College, Sydney. 
TbAplasma vermiformis, sp. nov. 
(Plate XT, Fig. 1 ; PL XXIII, Figs. 4 and 5.) 
Specific Characters . — Corallum probably fasciculate and large. Coral- 
lites long, erect, cylindrical, straight, united laterally by their walls, or 
simply contiguous and separated by variable interspaces ; section round, and 
diameter five millimetres. Epitlieca apparently quite smooth. Bourrelets 
represented by a series of delicate, regular, equal rings of very low convexity, 
and following one another closely. Septal lamellte twenty-eight to thirty, 
primary and secondary, and the separation distinctly marked ; spines very 
delicate and acute, the secondary remarkably short. Tabulae complete, 
distant, and regular, horizontal, very rarely slightly oblique. Gemmation 
compound-calicular-rejuvenescent, in two or four buds, the young corallites 
curving outwards from the parent. 
Observations . — This remarkably simple form appears to be quite 
distinct from T. Lonsdalei, and worthy of a name. It is distinguished by — 
(1) the limited number of septa; (2) regularity and simplicity of the tabulae ; 
(3) apparent absence of radiciform processes and tistulae. 
The long, simple corallites seem to be quite smooth externally, the 
regular, equal, smooth bourrelets of low convexity giving to the tubes much 
the appearance of a worm, or caterpillar. I think the corallum must be 
described as fasciculate, for, although the specimens before me are, in a great 
measure, composed of fragments lying in all directions, still sufficient 
corallites remain in parallel and sub-parallel positions to indicate that the 
form of the corallum was that of large bundles as described, at least nine 
inches high by seven inches broad. 
The septal lamellae arc less in number than in any other species, except 
one ; and are remarkable for their well-defined separation into primary and 
secondary, as indicated by the length of the spines. 
The tabulae are very regular, almost always horizontal, spaced widely 
apart, and resemble the rungs of a ladder. In a transverse section the 
surface is always quite plain, without any trace of cut edges indicating the 
presence of irregular or vesicular tabulae. 
