Further PER:vrTAx Corals froai Western Australia. 
()0 
priority ov'er Monilopom, Tho genus extends from the Devonian through the 
C'arbonilerous to the Permian, and characterises the Oy<ith(i.ro)iia phase of 
.sedimentation. 
Cladochonus nicholsoni (Etheridge). 
Mon'dopom nicholsoni Etheridge, 1914, p. 14, pi. i., figs. 2-4 ; pi. vii., fig. 4 ; Permian 
{‘i rpj)er Artinskian), Mt. iManiiion, Kinifierley. VV.A. 
Monilopora nicholsoni: Etherklge, 1918, pi. xxxix., figs. 2, 3, Permian, Paliuauiiigarra, 
Mt. .Mariniou, W,A. 
non Monilopora ? nicholsoni ; Hill. 1937. a, p. 59, pi. i., figs. 23, 24, text-figs. 19, 11, from 
Callytharra, which is Cladochonus striatns s]). nov. 
Type Materud : Of the syntypes, only a fragment, Australian Museum 
F 16418, has so far Ixhmi found. From it was cut the section figured Ethei’idge, 
1914, pi. vii., fig. 4. Tho s]3ecimeus figured Etheridge, 1918, [)I. xxxix., tigs. 
2, 3, are Australian Museum FI 6820 anti F16712 resptictively fn)m Halmauing- 
arra, Mt. Alarmiou. These are conspecihe with tfie tyfx^ maitniat, aiid are 
described ix>low. 
Diagnosis : l^ifurcating, free branchtis, 4*5 to 7 mm. thick, with success- 
ive corallilt's on o]i})osite sides of a branch, tlie diameter at the tnlge of tho 
ealiet' being constantly 4*5 mm. 
Deseri piioif- (of specimens from Halmaningarra) : Tlu^ diarntfi-er of the 
fnH> branclu's, memsun'd at- right angles to the plants of the t^alie.t^s, is from 
4*5 mm. to 7 mm., most fragments having approximatt'ly the sarnie diamett'c 
top and bottom, t'xcept at the poi7it- where hifui'cation txuMirs ; a l)ran('h of 
7 mm. avt^i-age dianu>ter f‘X[)ande.d to 8-5 mm. at sueh a point. 'The tmgh^ he- 
tweem tlu‘ products of bifurcation is about 3t) ; the distaiuM^ hiUwcMni bifuren- 
tions varies, an<l new branclu's are in a, phme at right a-ngles to tix* plaint of tlie 
caiieal opening^;. (^alieal openings are (drcular, and fairly rtjgularly 4‘5mni. 
in dianK'ter, evt'ii when the Itra^neln^s ant shtnder. 44ioy ar(' also fairly iMtgu- 
larly s]:)ac<Ml, therit being from 8 mm. tt) 10 mm. botwtten flat (ulge of the iow(a* 
Up of one eoi'allite to tliat of t-lie next- above. Tint hnvei' lip of tite caliee is 
■sliarp, hut not eontiiunsl into a ledge, tint sharptntss being dm' to the obliquity 
of the luuK'u to tint Ijraueli, which is aJ>oiit 45 . 'Pin' calic(ts alternat-e on 
■opposite sides of a braneli, each hra-ueh usually havitig t-wo vei'tiea.l rows of 
calic(*s, though Just Ix'foi'tt hifuntation tlutre ma->' he irr(tgularily. tkich 
■calice arises from the u})per part of tlie Ijase of tint out' h(4ov\-. The calical 
opiaiing extemls inwards with a very gradual and r(\gular decri'use in dianuder 
for at l(tast 4 mm., and thent ant signs of soptai ridgi's in its ujipi'r [larts. 
EtlxM'idgr's thin section shows ntticular tissue lining its lowei' parts. 
Banarks : Tlu' re})tant parts of tho corallum from whieli tln'sit fi-ee 
hrauclu'S H,ro pi’esumed to lia,ve arisen, ar(t as yet unknown. In tin' ( dndamiin' 
fault block, near Silverwood, Qmtenslaud, and in the (k)ral Stag(t of tint S])ring- 
sur(‘ District, Quci'iislaiid, fragnxtnts \A'lios(t dinu'nsions cori'c'spcjud to those of 
th(' Halmaningarra .s]xx*im(tns c'xectpt that the calical (slges may h«t 5 mm. in 
dianx'h'r rather than 4*5 mm. occur, assoeiated with otlif>r ( 'ladochonid 
fragments t>f diffi'ntut proiiortions, but wlii<4i yt't may prove fo h(t t his species, 
and with Thanmopora ivilklnsonl ( Id-heridg(t). In vi(‘v\’ of the ahundaiice of 
, specimens of <lifferent pnjport ions with tkose wit h characterist i(' projxji’tious 
at these two Quetaisland loeaIiti(\s. it is inifiortant to obtain more syntypes of 
C. nicJiolsoni,, in onUs- to (U'tino tlu^ range of variation possible in tiie sj'tecies. 
Cladocho)nos heecheri (draha-u, (Jertli, 1921, pi. cxiix., fig. 12) and (C magnns 
(k'rtli (id. tigs. 1(1, 11) from the Middle Permian of l3asU>o, Timor, are e-vt^n 
larger than this Australian sjxx*i('s, but their dirmaisious are attaiiuMl l)v a 
specimen in the lTii\ (‘rsity of (^mxnisland fi'om Cressbrook Cn^ek, mxir Esk. 
