A REVISION or SOME Previously Described Species of Bryozoa 193 
FROM THE Upper Palaeozoic of Western Australia. 
I^retnall (1926, p. 31) (lf;scrib('(l Aeiomocladia as a new genus “related 
to Finnatopora Vines” the genotype b(‘ing Aetom,ocladia ambrosoides Bretnall, 
from tlie Gascoyne River Distri(^t, W.A., and Fossil Hill, Wyndhain River, 
W.A. Bretnall did not study tlu^ inbTnal structure of tlu^ g(‘noty[)e, and 
it has therefore been considered a member of the AcanthocladiidatL The 
internal structure, as is shown under the description of the species given 
below, is the same as that described by Bassler and Moore for species of Gonio- 
(iladia, and by Shulga-Nesterenko for Goniocladia and Ramipora, and indicates 
that Aetomocladia is a member of the Sulcoreteporidae allied to these genera ; 
the form of the colony separates Aetomocladia from Goniocladia., and indicates 
identity with Ramipora (sens. str.). 
Ramipora ambrosoides nh''tnall). 
(Plate I., figs. 3-5 ; plate, IT., figs. C-F.) 
Aetomocladia, ambrosoides Ihvtnall, 1926, W.A. Geol. H'urvey, Bull. 88, 
p. 21, pi. I., fig. 4. 
Aetomocladia ambrosoides Bretnall, Hosking, 1931, dour. Roy. Foe. W.A.y 
Vol. XVII. , p. 12, pi, IV., figs. 5-6. 
Aetomocladia a'tubrosoides Bretnall, Chapman, in Baggatt, Jour. Roif. 
Hoc. 7V..S.W., Vol. LXX., pp. 106, 128, 148, 
Aetomocladia a')uhrosoid,es Bretnall, Raggatt and Fletcher, 1937, Australian 
Museum Records, Vol. XX., No. 2, p. 173. 
Acanthocladia acuticostata Bassler, 1929, Paldontoloyie von Thnor, Lief. 
XVI., XXVIll., p. 85, pi. 20 (CCXLIV.), fig. 13. 
Lectotype : Specimen 2 /2405B, Western Australian Geologi(^al Sur\-(‘y 
Collection; on specimen figuixul by lh’(‘tnall, 1926, ])1. 111. 
Horizon and locality : Bedween th(> top of the Lyons Series and the top 
of the Byro Series, Gascoyne Riv('r District, W.A. 
Fine Ramipora, with from three to jive rows e)f zooecial apertures on each 
side of the inesial lamina. 
Since the lectotype does not show the form of the colony very well, para- 
types from the same locality, and from tlie ('allytharra Stage at Fossil Hill, 
W^mdham Rivei-, and a number of specimens from the type locality of the 
('allytharra Stage in the Wooramel River District, and from the Nooncanbah 
Series in the Kimb(U‘l(‘y District have been used for this description ; the 
measiiD'inents given, liowever, were taken only on the lectotyp(^ and otlior 
specimens on the same piece of shale. 
The bas(' of the zoarium is not shown on any of the specimens ; the 
zoarium is pinnate ; the branches are bifoliate, and division of the branches 
takes place in a piano at right angles to the mesial lamina. Lateral (scicondary) 
branches are given off from the main stem, and thc'inselves give off tertiary 
branches which usually j^ass straight from one secondary bi-anch to another, 
but which rarely pass outwards obliquely and join to form a further set of 
branches. Subsidiai-y branches appear generally to originate at th(‘ same 
level on opposite sides of a branch, but actually one is nearly always given 
off very slightly before the otlier, as is shown by the junction of tlie mesial 
laminae of the lateral branches with that of the original branch ; very rarely 
the lateral branches on opposite sides are more widely separated. The dis- 
tance between the origins of two suc(;essive pairs of latei-al branches is from 
