Fig 59, A shows, above, fragments of the outer wall 
and the quadrate arrangement of the ends of intervallar 
rods; lower down is an oblique section through the 
intervallar mesh, reaching to the inner wall (IW). B 
shows the inner wall. 
Fig. 60 shows a conical specimen which may be a 
lower part of the same species. In this the outer wall 
shows a circular striated coat somewhat like those noted 
in the two previous species. 
Only these two specimens have been found. 
Dictyocyathus Macdonnelli, N.Sp. Plate XIL, Fig. 61. 
The specimen is conical, intervallum co-efficient 3 
mm.: 11 mm. Fairly numerous scattered rods cross the 
mtervallum. The preservation is too poor to show wall 
pores. Locality: Macdonnell Ranges, Central Australia. 
New Family DICTYOCOSCINIDAE. 
Two walls are present connected by an open mesh 
similar to that of Dictyocyathus. At intervals a series 
of horizontal sieve-plates fill the interstices of the mesh, 
forming a tabular structure resembling that of 
Coscinocyathus. Only one specimen has been found at 
the Ajax, for which we form the new genus 
Dictyocoscinus, having the above characters, with 
Dictyocoscinus Beltana as genotype; but Vologdin has 
` described three genera, Altaicyathus, Claruscyathus, and 
Tabulacyathus, and Taylor a genus Archaeosycon which 
have points of resemblance. 
Dictyocoscinus Beltana, New Genus and Species. Plate 
XIL, Fig. 62. 
An irregular cone; intervallum co-efficient about 4 
mm.: 12 mm. Outer wall not well seen; intervallum 
filled with a delicate open mesh similar to that of 
Dictyocyathus. At vertical intervals of 3 or 4 mm. 
horizontal sieve-plates fill the mesh, contiguous sieve- 
plates uniting to form a more or less horizontal 
“tabula” (A and B a, b); inner wall with numerous 
closely set pores about two to 1 mm. 
Only one fragment has been found. 
Family SPIROCYATHIDAE (Taylor). 
Four genera of this family occur at the Ajax, 
Protopharetra, Spirocyathus, Metafungia, and Pycnoido- 
cyathus; Vologdin describes another genus Retecyathus 
from Siberia. 
Genus PROTOPHARETRA (Bornemann). 
Taylor defines the genus as follows: “The intervallum 
is filled with irregular tissue, which is composed of 
flattened or cylindrical calcareous fibres, central cavity 
narrow." It is a little difficult to draw a clear line of 
division from Dictyocyathus on the one hand and 
Spirocyathus on the other. It is suggested that 
Dictyocyathus includes the forms in which the intervallar 
mesh is open, composed of light cylindrical rods running 
for the most part straight from node to node or from 
wall to wall; that Protopharetra include forms in which 
the intervallar tissue is more crowded and less rod-like, 
with little or no tendency to a radial or septal arrange- 
ment and with inner wall pores which are not converted 
into channels leading upwards and inwards into the 
central cavity; that Spirocyathus include forms with 
more or less radial orientation and with a tendency to 
large inner wall channels leading upwards and inwards 
into the central cavity. 
Protopharetra graphica (Bedford). Plate XIIT., Fig. 63. 
A shows a surface view (a) and longitudinal section 
(b) of a reconstructed specimen; B is a transverse, and 
C an oblique longitudinal section of a spitz. See also 
Part I, p. 4, 5, and Plate IV., Fig 2 
Genus SPIROCY ATHUS. 
Plate XIII, Fig. 64. 
Fig. 64 is given for comparison with other forms and 
to supplement Taylor's description. A is a sketch, 
natural size, to show the general form; the small ex- 
crescence on the left is a young Protopharetra graphica 
grafted on to the Spirocyathus. The outer wall has 
numerous small pores, about 4 to 1 mm., like those shown 
in Fig. 66, C; Taylor does not seem to have seen these, 
as, like so many specimens in this order the outer wall 
is often obscured by secondary silicification. B is a 
radial longitudinal section showing septa and synaptı- 
culae. C is a view of the natural rim of a specimen. 
D shows the inner wall pores which are regularly 
arranged, about 1 mm. apart, and lead upwards and 
inwards into the centra] cavity. 
Spirocyathus irregularis (Taylor). 
Spirocyathus multifidus, N.Sp. Plate XIII., Fig. 65. 
Shape cylindro-conical, with slightly waved wall, 
similar to S. irregularis. Intervallum co-efficient 4 mm.; 
13 mm. The outer wall pores are obscured. The 
intervallar tissue is on a very fine scale; it shows con- 
siderable radia] tendency and the curvature of the septal 
and synapticular lines in radial section is marked. The 
inner wall pores are numerous, 2 or 3 to 1 mm., and 
do not lead upwards and inwards into the central cavity. 
The wide intervallum distinguishes it from Protopharetra 
graphica, and the fineness of structure distinguishes it 
from other Spirocyathi. A shows a transverse section; 
B a radial longitudinal section;; C a tangential longi- 
tudinal section of inner wall and subjacent tissue. 
Spirocyathus ptychophragma. Plate XIII., Fig. 66, 
and Plate XIV., Fig. 67. 
This species was described by Taylor as Pycnoido- 
cyathus ptychophragma. It may be distinguished from 
