marked at the outer wall (Fig. 148 E). The inner wall 
is similar to the outer. In both walls about four or five 
rows of pores are present in each intersept. 
New Species Archaeocyathus brunhilda. 
Only one specimen has been found (Fig. 149 A). It 
is conical, with intervallum coefficient 24 mm. : 10 mm. 
The species, in many details, resemble A. floreus, but 
the septa are much closer and the outer wall is not 
bulged outwards in the intersepts. The outer wall pores 
are in separate clearly-defined vertical rows about 1/3 
mm. apart, with slight vertical ridges between the rows 
(Fig. 149 C). The septa are about 1 mm. apart, and 48 
are present in the specimen; (in 4. floreus there would 
only be a dozen in a specimen of similar size); septal 
pores are confined to a single row of large pores close 
to the outer wall (Fig. 149 E). The inner wall is a stout 
structure with large, fairly regular pores, well separated 
from their neighbors; no stirrup pores are present; there 
is either one or else two alterating rows of pores to the 
intersept, and occasionally the place of a single pore is 
taken by a close pair of smaller pores (Fig. 149 D) ; the 
inner surface of the wall is somewhat wrinkled. 
New Species Archaeocyathus carmen. 
The only specimen found is a small cone with bulging 
wall (Fig. 150A). The intervallum coefficient is 
l mm, : 23 mm. The outer wall has extremely minute 
pores regularly arranged in vertical rows; there are about 
eight of these rows to the mm., and low. vertical ridges 
project between the rows (Fig, 150 C). Hardly any 
other Archaeo has been seen with such minute wall pores. 
The septa are close, hardly 4 mm. apart. The inner 
wall is rather a complex structure with horizontal bars 
and stirrup pores at the inner ends of the septa (Fig. 
150B, D); the structure somewhat resembles A. 
retezona. The material is too small for further dissec- 
tion to see if any further septal pores are present. 
New Species Archaeocyathus josephina. 
Only one fragment ha been found (Fig. 151 A, B); it 
is a minute conical form with an intervallum coefficient 
1 mm, : 2 mm. The septa are remote, about 1 mm. 
apart. The outer wall appears to have comparatively 
large pores, but is not well seen. The inner wall is very 
characteristic, as seen from the inner surface, the pores 
being arranged in regular horizontal rings, four to 1 
mm., with small anular shelves between. The wide 
intersepts (and the ? large outer wali pores) at once 
distinguish it from B. trachealis. 
New Species Archaeocyathus divaricatus. 
The single fragment from which this species is described 
was found after the present plates were finished, so it is 
not figured here, It is a nearly flat fragment of a large 
bowl; the intervallum width is 3 mm. and the septa are 
4 mm apart The wall, which appears to be outer, has 
fairly regular pores, three to 1 mm.; most of the inter- 
sepls have two rows with alternating pores, but often the 
pores are in horizontal pairs, and often, by disappear- 
36 
ance of the mid wall of such pairs, single wide pores are 
seen; above each pore is a little semi-lunar ridge (convex 
above), giving a nutmeg-greater appearance. The inner 
wall has a single row of wide polygonal pores filling the 
whole width of each intersept. The most distinctive 
feature of the species is the septal pores, which are in 
about eight divergent rows in each septum; the inner and 
outer rows regularly incline to and disappear in their ` 
respective walls and fresh rows appear near the centre 
of the septum. The septa are very porous and the 
arrangement of the pores is very marked, more so than 
in the only other Archaeo in which we have observed it, 
viz., Sigmocyathus didymoleichus (see Plate XXII, Fig. 
93 B). The taxonomic value of this feature deserves 
consideration. 
New Genus Cadniacyathus. 
Archaeocyathina with vertical flutes to: the outer 
surface, the furrows corresponding to the positions of 
the sepia; the inner wall with scale-like hooks projecting 
upwards and inwards into the central cavity. Cadnia 
is a place name near Beltana. The genotype is C. 
asperalus. 
New Species Cadniacyathus as peratus: 
Two well-preserved fragments have been found. The 
form is conical (Fig. 152 A); intervallum coefficient 
3 mm. : 13 mm. The septa average about 1 mm. apart, 
or 13 mm. at the outer wall, where the flutings corre- 
spond. Four or five fairly regular vertical rows of outer 
wall pores are present to each intersept; porés about four 
to 1 mn, (Fig. 152C). The inner wall pores are 
larger, two or three to 1 mm., usually in three a ternating 
rows to the intersept; between each pore and the one 
above or below it is a jagged plate projecting upwards 
and inwards into the central cavity (Fig. 152 D, E). 
Septal pores are in about seven rows through the width 
of the septum (Fig. 152 E). ۱ 
New Genus Zonacyathus. 
Species Zonacyaihus retevallum (equal Archaeocyathus 
retevallum, Bedford, 1934). 
Archaeocyathina with fine regularly arranged outer 
wall pores, closely set porous septa and an inner wall 
consisting of a reticular mesh of considerable thickness 
without a defined porous lamina. The genotype is 
Zonacyathus retevallum (described as Archaeocyathus 
relevallum, Bedford, 1934). The reason for separating 
this generically from Archaeocyathus retezona, Taylor, 
1910, which possesses a reticular mesh at the inner wall 
and might be considered for inclusion in the new genus, 
is that A. retezona has, as the inner component of its 
inner wall, a regular porous lamina just like the inner 
wall of A. ajax; we have found specimens intermediate 
between these two species, specimens which may perhaps 
be regarded as hybrids, and therefore consider 
A. retezona and A. ajax as closely related, and consider 
the net-zone of the former as a development of the stirrup 
pores of the latter. Zonacyathus retevallum is considered 
to be a quite different type from either of the above. In 
