porous layer; this is shown at the upper left-hand corner 
of the reconstruction, Fig. 96 (J). The septal pores are 
large and numerous, about one every two mm. The 
inner wall is a very strong, regular structure composed 
of very large canal-like pores, one row to each intersept, 
` leading upwards and inwards into the central cavity (ses 
Fig. 95, 96 (D), (E) ). These canals, in the upper 
part of the lip, may reach 2 mm. diameter and 5 mm. in 
length, and a transverse section usually cuts two of them 
successively at each intersept. 
The lower part of the cup is in some cases surrounded 
by a mass of exothecal tissue, shown in Fig. 96 (G), (J). 
We are deferring detailed consideration of the exothecal 
tissue which occurs in connection with several species of 
Archaeos, because, although apparently part of the 
organisms themselves, the alternative possibility has to 
be considered of its being a parasitic growth. Vologdin 
has described under the name Labyrinthomorpha a para- 
sitic form of Archaeo which envelops various Siberian 
species. We have noticed in the specimen shown in Fig. 
96 (G) that in another place the exothecal tissue en- 
velops a second quite distinct genus, with the tissues of 
which it appears as intimately connected as it does with 
those of the Beltanacyathus. 
The spitz of Beltanacyathus ionicus, embedded in the 
exothecal tissue, continues to show the characteristic 
structure down to a diameter of 2 mm. or less. but a few 
dissepiments are present in the intervallum. 
The genus is placed in the family Spirocyathidae on 
account of the strong resemblance of the inner wall to 
that of several forms of Spirocyathus and Pycnoidocya- 
thus; the cuter’ wall also appears to be of similar type 
to the outer walls of those genera. The straight septa 
and absence of synapticulae has already been noted in 
some species of Pycnoidocyathus. 
The form described by Taylor as Archaeocyathus 
Wirrialpensis appears to be another species of Beltana- 
. cyathus, differing in the lighter construction of the inner 
wall and the absence of the external flutings. 
A form apparently identical with Beltanacyathus 
іопісиз occurs at Curramulka, S.A.; Fig. 96 (F) shows 
the inner wall of a Curramulka specimen. 
Order ARCHAEOCYATHINA (Okulitch). 
New Family PUTAPACY ATHIDAE. 
New Genus and Species Putapacyathus 
Regularis. 
The new family, genus, and species is founded on a 
unique and very remarkable fragment from the Ajax 
limestone which is excellently preserved and enables all 
essential characters to be determined, with the exception 
of the base or spitz, which has not yet been found. The 
specimen has very specialised outer and inner walls, and 
numerous clearly defined tabulae, but septa are entirely 
wanting. The fragment is 35 mm. long, conical, 15 mm. 
diameter at upper and 10 mm. diameter at lower end. 
The intervallum coefficient is 24 mm.: 8 mm. (Fig. 
97 (A) ). The outer wall has on its inner surface regu- 
24 
lar vertical ridges, 3 to 1 mm.; these are crossed by 
narrower bars about 6 to 1 mm., and each oblong space 
so formed is again divided by a vertical partition so as 
to give an external surface regularly and quadrately 
porous, the pores about 6 to 1 mm. The inner wall is 
still more remarkable; it has a series of vertical ridges 
in two series, which alternately project into the inter- 
vallum and the central cavity, the ridges of either series 
being about j mm. apart. Each ridge has a vertical 
series of “stirrup” pores, so arranged that opposite each 
external ridge is an internal row of pores, and opposite 
each internal ridge is an external row of pores, whilst 
all pores communicate with tangential perforations in the 
centre line of the wall, thus giving a clear though indirect 
communication between central cavity and intervallum. 
Regularly arranged, nearly horizontal tabulae cross the 
intervallum at intervals of about 2 mm., and each tabula 
has numerous somewhat irregular pores about 5 to 1 
mm. No septa or other structures representing septa are 
present. The above described species, Putapacyathus 
regularis, is the genotype of the new genus, the name 
being taken from Putapa Gap, a prominent mountain 
feature near the Ajax Mine; (all vowels in Putapa are 
` short, the accent being on the first syllable). 
The family may be defined as Archaeocyathidae with 
ridged and regularly porous walls, with regularly 
arranged tabulae and absence of septa. The family may 
perhaps be regarded as derived from a Coscinocyathus- 
like form by reduction of septa, in the same manner аз 
Dokidocyathus has been regarded as derived from an 
Archaeocyathus-like form. Possibly the spitz, when 
found, will throw some light on this point. 
Vologdin has described from Siberia a minute form, 
Tabulacyathus, having tabulae and no septa, but the 
material is insufficient to decide whether the two forms 
“are genetically related or whether it is a case of parallel 
development; both appear to be very scarce and isolated 
types. 
? Order ARCHAEOCY ATHIN A. 
? Family COSCINOCY ATHIDAE. 
New Genus Sigmocoscinus. 
The genus may be defined as cups with regular straight 
| septa, tabulae of the normal Coscinocyathus type and 
continuous annular sigmoid plates inside the inner wall. 
The genotype is Sigmocoscinus sigma. 
New Species Sigmocoscinus sigma. 
The cup is tubular, conical, 30 mm. or more in length 
by about 9 mm. diameter in the upper part; intervallum 
cefficient 2 mm. : 5 mm. Septa are straight and regular, 
about 2/3 mm. apart. The outer-wall-pores are small, about 
4 to one mm., about three rows to each intersept, and are 
covered externally by overlapping annular plates, about 
4 of these occurring in each mm. of length (Fig. 98 (D)). 
The inner-wall-pores are larger, about 2 to one mm., one 
or two rows to each intersept, and are covered internally 
by annular sigmoid plates projecting into the central 
cavity, about 2 of them occurring in each mm. of length 
