66 
Dorothy Hill. 
spines. In all specimens the corallites open at right angles to the surface, 
thus differing from T. ^narmionensis, where they open obliquely. In the 
M 16 specimen, dilatation is not so excessive as in the others, and thin tabulae 
can be seen. Individual septal spines or trabeculae have not been dis- 
tinguished, though the sclerenchyme is fibrous. Etheridge may have included 
some specimens of T. iinmensa in his T. marmionensis, as his description of 
the latter covers coralla with corallites opening at right angles to the direc- 
tion of growth as well as those with corallites opening obliquely. The only 
two syntypes of T. marmionensis which I have seen, however, had their coral- 
lites opening obliquely. T. immensa or a very closely similar form occurs in 
association with Euryphyllum reidi at Castle Creek, Theodore, in an unknown 
horizon in the Queensland Bowen succession. 
Thamnopora marmionensis (Etheridge). 
Favosites marmionensis Etheridge, 1914, p, 13, pi. i., fig. 1 ; pi. ii., figs 2-4 ; pi. viii., fig. 
2. Permian, Mt. Marmion, Kiml.»erley District, Western Australia. 
Diarpiosis : Thamnopora forming largo lobate masses, with corail ite of 
two sizes opening obliquely to the surface, calices fi*equently with lower lip 
semi-circular, and with corallite walls becoming very thick distally ; with 
large irregular poi‘os, frecpient tabulae, and without septal spines. 
Remarks : The species differs from the eastern Australian T. wilkinsoni 
(Etheridge) in being lobate rather than ramose, and in having the calices 
closer, while the projection of the calical rim is low compared with that of T. 
wilkinsoni. 
Thamnopora aff. marmionensis (Etheridge) (Plate II., fig. 7). 
Material : A fragment in limonito (g) from the lower part of the Lino- 
prodiictns stage somewhat east of the Heliocoprion locality of Coolkilya Flat ; 
only the calical surface can be studied, and tins shows corallites of two sizes, 
most of the openings have one-half of their outline semicircular, repre>senting 
the lower lip, which, however, does not project, and the upper half polygonal, 
two or three short edges meeting at angles. This specimen is probably T. 
marmionensis, but the internal structure is obscured. A small lobate fragment 
(i) from high in the Calceolispongia stage at Station 25A, “ Upper worm track ” 
horizon north of Minilya River, witli thin walls and oblique calicos, which is 
probably T. marniionensis, but the calices are not clearly distinguishable into 
two sizes, and vary between 1 mm. and 1 • 5 mm. A worn, lobate fragment 
(b) from the highest beds exposed north-west of Station 23, in the lower part 
of the Linoproductiis stage, Minilya River, \vhich is probably T. martnionensis, 
although the corallite walls are thicker than in the sj-mtypes, being 1 mm. 
nr nearly 1 mm. throughout, and the septa appear to have donticulations 
resembling spines on their inner edges. A cylindrical fragment (d) from the 
lower part of the Linoproductus stage near Station 4A, north of Minilya River, 
whose internal structure is similar to that of (b). A cylindrical fragment 
(c) from the same horizon at Station 4A, north of Minilya River, closely 
resembling (b) and (d). All these are from tlie Wandagee beds. 
Remarks : One cannot be certain that these specimens, which are prob- 
ably conspecific, are T. marmionensis, because of their fragmentary nature, 
and because our knowledge of syntypes is very limited ; but the small, oblique 
corallites suggest that they are. I have seen nothing similar from eastern 
Australia. 
