New Species Flindersicyathus tabulatus. 
In the details of its tissues this species closely resem- 
bles F. decipiens. The outer wall is similar, with pores 
four to 1 mm.; the intervallar mesh is similar, three 
elements to 2 mm., or a little coarser, one to 
1 mm.; the inner wall is similar, with pores one to 1 mm, 
The special feature of the species is the presence of 
upwardly convex “growth tabulae”; these occur at 
irregular intervals, from 1 mm. to 10 mm. apart, and 
appear to indicate successive periods of growth of the 
sponge. At the end of such a period the cup was 
terminated by a convex porous wall, the following 
segment commencing with a narrower external diameter 
and expanding in its turn to a fresh convex termination. 
The species is shown on Plates XXVII, XXVIII, Figs. 
111 A, etc. Fig 111 A shows the tabulae in tangential 
longitudinal section, with the same enlarged in Fig. 
111 D. Fig. 111 E, F shows two views of a small 
terminated cup which is probably a comparatively young 
specimen of this species. The outer form of a mature 
specimen is that of a more or less cylindrical, externally 
corrugated tube. The intervallum coefficient is necessarily 
variable. In a fragment 8 cm. long it is 5 mm. : 5 mm. 
at the lower end, and 4 mm, : 13 mm. at the upper. - 
New Species Flindersicyathus macdonnelli. 
The only specimen of this species from the MacDonnell 
Ranges in Central Australia is, like the rest of material 
from that locality, poorly preserved in a highly siliceous 
stone. "The specimen is a short fragment of a cone about 
20 mm. long, with an intervallum coefficient of 5 mm. : 4 
mm, at the lower end, and of 7 mm. : 10 mm. at the 
upper end. The inner wall is of the type characteristic 
of the genus, with large pores, one : 1 mm., leading 
upwards and inwards. The intervallar tissue is only 
visible at two points, but is of similar character to 
other species of Flindersicyathus. The form is more 
conical than that of Ajax species. See Plate XXVIII, 
Figs. 112 A, B. à 
Genus Sigmo[ungia. 
Taylor in 1910 described a species Archaeofungia ajax, 
his specimen being difficult to make out in all its details 
owing to secondary silicification. There appear to be 
two genera at the Ajax, either of which is more or less 
consistent with Taylor's figure and description. We 
have described these in previous memoirs as Metafungia 
and Sigmojungia (see our Plate IV, Fig. 23, and Plate 
XIX, Figs. 81, 82). We used the termination -fungia 
to relate the specimens to Taylor's, but are still undecided 
as to which of our two genera is actually “Archaeo- 
fungia." Together with ‘other points of difference, in 
Sigmofungia “the inner wall pores are in vertical rows, 
each pore being separated from those above and below 
it by a sigmoidally curved plate" (see our Memoir No. 2, 
p. 16). All these forms are extreniely rare. 
New Species Sigmofungia fragilis. 
We have one fragment whose tissues are more delicate 
and on a finer scale than those of S. flindersi, the septa 
being 4 mm. apart as against about 1 mm. in the latter, 
and the synapticulae finer and much more numerous. 
Sigmoidal plates are present in the inner wall pores. 
The intervallum coefficient appears to be about 4 
mm. : 10 mm. Details are shown on Plate XXVIII, 
Fig. 114 A, B, and the relative dimensions may be 
compared with Fig. 113 (Metafungia) and Fig. 115, 
which shows another species of Sigmofungia, the three 
figures being drawn to the same scale. 
New Species or Variety Sigmofungia tabularis. 
We have found two specimens, agreeing in other 
respects with Sigmofungia flindersi, which show definite 
tabular structures. One of these specimens is shown in 
transverse/oblique section in Fig. 115. At the lower 
right corner is part of one tabula lying in the plane of 
the section, which is here transverse. The tabula is 
here seen to have an irregular structure of a coarse mesh 
whose interstices are occupied by a finer mesh. At the 
left hand of the figure the section becomes oblique, and 
another tabula is seen cut across; also here the sigmoid 
plates of the inner wall become visible. "The intervallum 
coefficient is 5 mm. : 6 mm. The other specimen (not. 
figured) shows, in tangential longitudinal section, five 
clearly-defined curved tabulae in a length of ten mm., 
and would at first sight be’ mistaken for a tangential 
section of a Coscinocyathus. 
New Genus Copleicyathus. 
The fragments on which this remarkable genus is based 
were found in the same small outcrop near the “Paint 
Mine," Beltana, in which Beltanacyathus occurs. A 
central cavity is present, at least in the upper part. 
Septa are numerous and are of “wire-netting” character; 
although they are in places traceable right across the 
intervallum, they are very irregular and more often curve 
and anastomose with neighboring septa. The inner wall 
is of very unusual type, being a thick, felted, mass of 
curved anastomosing rods continuous outwardly with 
the septal mesh. The only species yet found is the 
genotype C. confertus. The form appears to be 
sufficiently distinctive to require a new family, 
Copleicyathidae, for its reception. The question of its 
ordinal relationship is deferred until a full revision can 
be attempted, but it may be placed provisionally with 
the Metacyalhina. 
New Species Copleicyathus confertus. 
This conforms to the generic description just given; 
the intervallum coefficient of the type specimen is 4 
mm. : 5 mm. The irregular septa are about $ mm. 
apart. The thickness of the mass of close-set felted 
fibres forming the inner wall is 14 mm., and we cannot 
make out any definite porous lamina in connection with 
it The outer wall is obscured externally by secondary 
silicification; it seems to be a network of small irregular 
pores, but the preservation is too poor to make this 
certain. The type specimen is shown in transverse and 
longitudinal sections in Figs. 116 A, B: the latter section 
is tangential, grazing the outer surface of the mass of 
