fibres which forms the inner wall. The specimen shows 
ón one surface a silicified mass outside the outer wall, 
figured in Figs. 116 C, D; at first we thought this might 
“be exothecal tissue, but probably this is not so. Fig. 
116 F shows a smaller variety in which the septa are 
more regularly radial. Fig. 116 E shows a small 
specimen, also from the same mass of rock, which might 
perhaps correspond to an early stage of C. confertus, 
but, of course, we have as yet no direct evidence as to 
the mode of growth of that species. 
New Genus Spirillicyathus. 
These are small forms from the “Paint Mine.” In the 
genotype S. tenuis the outer wall has irregular pores, 
formed by anastomosis of the underlying septal elements 
(Fig. 118 C). The septa are built of a series of radial 
and longitudinal rods (Fig. 118 B, E) and are connected 
by tangential rods or “synapticulae.” As seen in trans- 
verse section, the septa often run fairly straight from 
inner to outer wall, but they also often bifurcate and 
anastomose, particularly near the outer wall. The inner 
wall is a definite layer, with small circular pores, about 
two rows to the intersept. As far as we know the form 
grows from a spitz having essentially the same character, ` 
New Species Spirillicyathus tenuis. 
This has the characters above mentioned. The type 
specimen is insufficient to show the general shape, which 
is, perhaps, roughly cylindrical. The intervallum 
coefficient is 24 mm. : 14 mm., the central cavity being 
very narrow. The irregular septa are about 4 mm. apart. 
Synapticulae are numerous. The specimen is shown in 
Figs. 118 B-E. A small spitz, shown in Fig. 118 A, is 
from the same mass of rock, and may, perhaps, be of 
this species. 
New Species Spirillicyathus pigmentum. 
The little specimen to which we give this name is also 
from the “Paint Mine” outcrop. It is a small cone 
(Fig. 117 A) having an intervallum coefficient of 
2 mm. : 2 mm. at the upper end. It agrees with the 
former species in the character of the outer wall and 
in the anastomosing branching septa, and in the defined, 
porous inner wall. But in this species the inner wall 
pores are larger, with one row of pores to the intersept 
and the septa are rather in the form of porous laminae 
than of trabecular mesh. The septa are about 2/3 mm. 
apart. Synapticulae (if present) are not a regular 
feature. Figs, 117 B-E show details of the structure. 
In using the generic name to cover these two rather 
dissimilar species, we are making a temporary conveni- 
ence of it for the reception of these and other scarce 
and somewhat nondescript little forms whose relationship 
to better-known and commoner genera is not yet clear. 
The character of the outer wall and the irregular septa 
remove them from Archaeocyathus and related genera. 
The septa are too predominantly radial for Proto- 
pharetra, and the inner wall pores have not the 
specialised form of Flindersicyathus. There is no evi- 
dence that they grow from an Archaeopharetra-like spitz 
as do the Metacyathina and Paranacyathus. 
30 
New Species Syringocnema. spriggi. 
We are indebted to Mr. Reginald Sprigg, a student at 
the Adelaide University, for the specimens of this pe 
which he collected at Ardrossan, S.A. There are also 
probably other new species of Archaeos in material 
collected by Mr. Sprigg as well as by ourselves in that 
and other localities which we hope to deal with in a 
later paper. In the meantime it is interesting to record 
that Mr. Sprigg has found at Ardrossan a specimen of 
Taylor's species, Dokidocyathus simplicissimus, and that 
we note the occurrence there of Bronchocyathus 
trachealis. Some of the more aberrant forms from 
Ardrossan are referred to later in the present paper. 
Syringocnema spriggi differs from the Ajax form S. 
[avus (Taylor) by its long, narrow, cylindrical shape 
and its narrow intervallum. In a length of 50 mm. it 
varies little from a diameter of 10 mm., and an inter- 
vallum coefficient of 2 mm. : 6 mm.; whereas the Ajax 
species increases in 40 mm. length from a diameter of 
17 mm, at the bottom to 25 mm. at the top, and has an 
intervallum coeficient of 6 mm. : 6 mm. The Ardrossan 
species is shown in Plate XXIX, Figs. 119 A-D; the pian 
oi construction agrees with that of the Ajax species. 
Order METACYATHINA. 
Genus Archaeopharetra. 
In our second paper we described and figured a small 
organism under the name of Archaeopharetra typica. 
We have since had the opportunity to examine a series of 
specimeas of the same or similar character, and they 
yield results of considerable importance for the classi- 
fication of the Pleospongia. It is highly probable that 
some or all of the varieties of Archaeopharetra are 
actually “spitzes” of members of the order Metacyathina, 
but until they can be definitely allocated to the relative 
adult forms the name Archaeopharetra may still be used 
for convenience. The outstanding feature of these 
spitzes is that they originate as minute conical tubes with 
transverse partitions; see Plates XXIX, XXX, particu- 
larly the tower parts of Figs. 120 A, 120 E, 123 A. We 
have not seen any pores either in the tube-wall or the 
partitions in these earliest stages. As the tube enlarges, 
straight or curved rods grow upwards and downwards 
from the transverse partitions and may either hang freely 
as straight or hooked processes or may pass as vertical 
connecting rods from one partition to the next; these 
rods are well seen in Figs. 120 C, D. An occasional 
pore occurs in the partitions at this stage; one such is 
present in the lowest partition of Fig. 120 C, though it 
is not seen in the drawing. The outer surface of the tube 
is often covered by a circularly striated coating, seen in 
Figs. 120 C, 121 A, 122 A, 123 A. 
Archaeopharetra typica (Bedford, 1936). 
The specimens shown in Figs 120 A-E resemble this 
species, though there are points of difference among 
them. Fig. 120 A seems to be quickly replacing its 
basal transversely partitioned structure by a coarse 
“spirocyathus”-like structure, without as yet any sign of 
an inner wall. Fig. 120 B retains its transverse par- 
