۹ d y 3 ” 
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= Memoirs of the Kyancutta Museum 
ANS KYANCUTTA, South Australia 
May, 1939 
p | | | Development and Classification of 
٠' Archaeos (Pleospongia) . | d 
By R. & J. Bedford 
We attempt in the present paper to base a natural 
classification of the Archaeos on the character of the 
earliest known stages of development of their skeleton. 
These stages, or “spitzes,” 
is etched siliceous material from the Ajax Mine, South 
Australia. In attempting to correlate these forms with 
overseas species of which details of development are 
not yet known, we realise that such correlation is 
necessarily provisional; but, as a very large amount of 
work will have to be done before a complete and satis- 
factory classification can be expected, a provisional 
scheme may be serviceable if only by calling attention 
to the need for further developmental studies. 
In the present paper descriptions are given of the 
following new orders, families, genera, and species: 
Family Rhizacyathidae. 
Genus Rhizacyathus. 
Species Acanthinocyathus transiens. 
Order Ajacicyathina. 
Family Alphacyathidae. 
Genus Alphacyathus. - 
Species Alphacyathus zero. 
Family Ajacicyathidae. 
Genus ‘Ajacicyathus. 
Family Sigmocoscinidae. ! 
Species Archaeopharetra vologdini. 
Family Flindersicyathidae. 
Order Crommyocyathina. 
Family Exocyathidae. 
Order MONOCYANTHINA (Okulitch). 
Single-walled, slightly tapering, porous tubes. They 
appear to be the most primitive adult sponges and 
resemble the Olynthus stage of sponges. The largest 
“species (porosus) has very numerous uniform pores, 
` regularly arranged in quincunx, the wall being almost 
are at present best known: 
identical with the outer wall of such an Archaeo as 
Dokidocyathus. The smallest species (irregularis) has 
irregularly scattered circular pores, most of which are 
on little papillae. Another species (spinosus) has 
a wall of regular more open reticular texture with 
tubercles projecting outwards from the nodes. 
Family MONOCYATHIDAE (Bedford). 
This, with characters as above, is the typical family. 
Vologdin (Problems of Palaeontology, Moscow, 1937) 
places Monocyathus with Rhabdocyathus sibiricus (von 
Toll) in a family Rhabdocyathidae, considering these 
two forms as alike in structure. We cannot agree with 
this. Von Toll’s description of Rhabdocyathus is as 
follows (Memoires de L'Academic Imperiale des Sci. de 
St. Petersbourg, 1899): “The case consists of a cylin- 
drical or subcylindrical rod-shaped cup, whose walls are 
formed of thin calcareous lamellae. In the lower part 
of the cup these lamellae are numerous and arranged 
concentrically; as they are separated by a space they 
form an inner and an outer wall of the cup. Stout 
little tubes go out from the inner wall, traverse the: 
outer wall, and form by their exit the outer pores. 
Some of the little tubes grow out beyond the outer 
wall, whereby in the transverse section their lumina are, 
. visible as excentric openings beside the outer wall. In 
the upper part of the Rhabdocyathus cup inner’ and 
outer walls lie close together, but in transverse sections 
outer and particularly inner walls show -as thicker 
lamellae, which contrasts as strongly refracting layers 
. with the middle parts of the cup-wall which are formed 
of fine but. compacted lamellae. . The pores are ar- 
2 27 
ranged in regular rows. 
Von Toll, in another passage, refers to “the inner 
wall, formed by simple infolding" and says “pores 
traverse the closely opposed walls." 
۱ 
Von Toll regarded Rhabdocyathus as a primitive, 
