17() 
JOAX M. Ckockfokd. 
0-11 by 0 06 mm. in diameter, and are surrounded by well-developed 
peristomes; they may be closed by a calcareous plate, frequently showing a 
small central perforation; the whole of the celluliferous surface shows strong 
ridges and grooves around and between the ai:>ertures. There are five, less 
often four, apertures to a fenestrule, the distance between the centres of 
successive apertures being from 0-25 to 0-35 mm.; about thirty-one apertures 
occur in 10 mm. Small nodes are irregularly developed. The fenestrules are 
sub-rectangular, from 1-15 to 1-36 mm. in length, and from 0-3 to 0-95 mm. 
in width; the dissepiments, which expand only slightly at their junction 
with the branches, are from 0-17 to 0-29 mm. in width. On the celluliferous 
surface the dissepiments are evenly rounded, and each shows four or five 
strong transverse ridges and grooves. On the reverse surface both brancht 
and dissepiments are rather sharply rounded; the branches are rather thicker 
than the dissepiments, and show numeroxis fine longitudinal striae w^hen they 
are very slightly Avorn ; a roAV of fine tubercles may occur across the back of 
a branch at its junction Avith a dissepiment, but these are not ahvays 
develope'd. The dissei)iments shoAv fine transverse ridges and grooves. Bifur- 
cation of the branches occurs at intetwals of 5 mm. or more. 
Remarks: Pohjpova virga Laseroii, AA'hich occurs in the Upper Marine 
Series in New South Wales, is a larger form, with usually three rows of 
zooecia. 
Polypora retificis sp. nov. 
Plate 2. Fig. 4. 
llolotype : Specimen 20951, L niA'ersity of estern Australia Collection.- 
(Coll C. Teichert and H. Coley). 
Horizon and locality: Calceolispongia Stage of the Wandagee Series; 
Syncline on iNIinilya Ri\'er, half mile AA est of Coolkilya Pool. 
Polypora with three roivs of zooecia, and four zooecia to a fenestmle; 
nodes veri/ large, Imt infrequentlg developed. 
Tlie form of the colony is not shoAvn; there are 0 fenestrules vertically,, 
and 15 to 17 branches horizonttdly, in 10 mm. The branches are straight 
or slightly [lexuous on the obverse surface, and normally sIioav three roAVs 
of zooecial apertures, Avith four just before, and tAvo for about two fenes- 
trules after, branching; there is a slight carina where only tAvo rows ot 
apertures occur. Large nodes about 0-22 mm. in diameter are iriegularh 
and infrequently developed, generally in the mid-line of the branch. There 
are four apertures in the length of one fenestrule and one dissepiment, 
either one or two of these being placed opposite the end of the disse})iment ; 
the distmice between the centres of successive apertures is from 0-24 to 0-.-.S 
min., and about thirty-three apertures occur in 10 mm. The apertures are 
circular, about 0-11 mm. in diameter, and show thin peristomes; over a 
large part of the surface the apertures have been enlarged, and the peri- 
stomes remov(’d, by Aveathering. The apertures may encroach on the end:^ 
of the dissepiments, but extra cells do not normally occur; in one place 
two branches each shoAving tAVo rows of zooecia coalesce tor a short distance 
after their separate bifurcations. The fenestrules are oval on the cellu- 
liferous surface, and are from 0-67 to 0-8 mm. long, and from 0-33 to 0 5 
mm. Avide: the Avidth of the dissepiments is from 0-41 to 0-6 nnn., and the 
length of one fenesti’ule and one dissepiment is from 1*16 to 1-38 mm. On 
the reverse surface both branches and dissejiiments are rounded, and the 
fenestrules appear round or OA'al; the dissepiments are generally slighth 
