Occurrence of dyctyid hexactinellid sponges in the Upper Devonian•of the Holy Cross Mts

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Vol. 31 ^t NO'. 3~4 ^" ^,"

J. 'iKiEITH ,RIOOY, IGRZEGORZ RAOKI & ToMAsz WRZOLEK

.. ; ....

acta'"

geologlea pOlonlqa

'Wtirszawa :

f98·1

" ",

,',.

Occurrence' ofdyctyid ' hexactinellid sponges in. the Upper Devoman · of 'the Holy Cross Mts '

ABSTRACT: Hexadi.ne'l\1i.d ~o.n.ges with rigid, Jat~aHy, fused, dictyoni,ne .s:k:ele~

tons are ;reported f:r.om the Frasnian ;racks of the Holy Cl'OIsos Mts, Central Po~and.

Thiis oceur.rence, with lIleady oontemp'oraryUndescrl'bed· f6Ims from BelgiUIll arid Western Australia, eX't.einld if;he ;range m the HexaoetilIlosa 'ba,ck from 'l;.heTrias~k,

, the prev'J,ously ea!l'lie:st descr:~bed .s:pcmges .of 1Jhe o.rder.

JNTRODUCT10N

HeXlactinellid sponges, axe ll"elaltiveJ.y rare· ou1side of North AmerilCa whe!l"e HalIi1. & Cla:rk)e (1¹8'98) described the famous Devonian dictyoopon- g.es of nO!I"theastern UiIllited States.

Recent

cdI.lec'tions from the Late De- vonda!n F:rasnian :r0iCks of 'the Holy Mlts !in Cen'tlrai Poland (cf, Text-figs 1-2) include seVle.rall spec:ilIliens ,af 'heXlao1linelLids of unusua[ SigIlJifica:nce.

,

These fossils and other associated spongES a:re the subject of an ex~ed

pa per now in preparation..

Devonian sponges of the HOlly Cross Mts hav.e been discov;erec:i at the begi:n:hin:g ofthds centulI'Y. Giirrich ,(1901, p. 356) reported a singJe specimen assiognedaS ?Protospoo,gia flrom. !the Famermian of the Kie1'Ce . region. Solbolev 'ClI909.

uno,

t:911, 19'12) found numerous spong'es in a small outcrop south of KowaILa t(GaI~ziJce synciine, Text-'f~g. 1). Due to the ,Ill.alS\S OOCU!ITeIlce oIf sponges, Sobo1ev (1911, 1912) called the deposits the ~pongefacies, ibei.:n;g a locail variety of the biO'he:rmal· facies of the Kadz1eLnia .liiJmestone (!lower part of the Upper Devoruan). Sobolev did not inv€St:igate his collection' pa!leontologically, but he only reported i,t, as being strongly dif~.t;entiate<:t, oomposadofthe Hexactinellida r{sub- oNler Dictyonina), and similar to the assemblage described by: HaLl &

Claaike(1898) from the Devonian of New Yo:rGt. There was given a list of associated :fossi1s, illladdy hrachiopods and corals, aIIld theillust.raltion .of a spong,e-bearing llmeston'e (Sobolev 1910, '1911}. '

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164 ^J.KEITH RIGBY '" al.

Besides a few general :rema:rtks,so.m€!times ~11ustrai1;ed, on ,the spang'es at KiOWala (lDeimb.iDSka-R6Z!kowska 19418, Samsanowd.Cz 1962, Kota,ilski. 1959, Filonowicz 1973). paleontologiJCaJ. determinations bave been OIff.ered by Siamira<hki l(lJ92i2) who mentions "1lh.e peculiar litmelsron,e, containing sili- cirfied acoummulations of sponges", belonging tto such g'ene:ra known from 'the Jurassic' 'CO'JllmOIl1y and Cretaceous up untill !IlOW as Craticu- laria, Sporadopyle,aoo Tremadictyon. On. the other hantl, iMay:r _ (1'929) gave a .preliminary report of 'the paileon1taJ..ogdcal :research on sponges from -Cmrnocki's cO'liection, and he emphaSized also an unique character of the assettnblage thaif; oonlbained \both "Sd.lurian" I{Pyritonema - 3 new species, Aulocopium - 2

llleW

^species,Rhopalospongia, Astylomanon, Ca- ryomanon) and' "iMesozoic" !types of sponge'! (Craticularia, S-poradopyle, Tremadictyon, Cylindrophyma, old~t rrepresentatives of Ventricul~ti:dae

- Paraventriculites - with IStron!gJy <folded wall).

The cdI.1eotOOn of aoove 100 specimens, descrilbed preliminaJ:-ly tin the p:i-.esent note, co.:nias moo'tlyfrom the new outcrop of the J az.wica QUa.Ny . in the southiem ManIb· of 'the Gal£:Zioe sytncli.noe, about 3 'km to the weSt

·from llie Ko'Wala spong,e-bearin:g :exposul"e I(rl'ext..,fttg. 1B). The last men- 1rl!oned Place yi,eJidedonly few specimens, collected. :from road cut (a'p-

o 2 4

' ... - .... ' -. . . . -1' km

Fi'g. 1. Location ,of' iSponge"\beaTing exposures .in 'P-oland (A), and in the western pan af the iHoIly Cross iMts (B); teiken after SzUlJczewski (1971, Text-lf.ig. 1; sim- pLijie:l)

1 Cambrian; OrodoVl.cian and >Sllurian;a Lower and Middle Devonian, 3 Upper Devon.lan, 4 Lower Carboniferous. ^$PoSt~Variscan cover (Z~chsteln .... Jurassic) .

J :.... Jatwica Quar.:ry, R - Eowala Toad cu't; K -- Kowala Tailr-oald cut, W W()la Quarry

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ACTA GEOLOG,ICA POLONICA, VOL. 31 J. REITH IHGBY, G. RACK! & T. WRZOLEK., F'lG. 2

Upper Devonian sponge-bearing deposits exposed at the Jaiwica Quarry

o

_ _ _ _ _ _ . . .

20

1 rn

~.2 _~_{--- 3}

--

^~4

KOWAlA

...

' . ' ... . ... . ... .

' ... .

...

.. . . . . . .

JAZWICA

Quarry

B

10

o

L:]3

H3i1

HIG~· ^?

]

H, ... .

Fb' B ?

? E ... . D

\

?

~4 Ir:Jls ~6

2: ~ Z Z IJ.I

~ c( u.

z Cl:

t= w

>

CJ

A - Sk,ekh of the eastern wall, upper exploitational :levelI at the Jazwioa Quarry (after Racki & Zapasnik 1979); arrowed are the sponge - bearing nodu:lar ilim'estolll€Js i( see T,ext-fig. 2C)

G-H - Frasnian lithologi'c complexes (see Text-fig, 2.B), I - Upper Famenni,an shale-mar.ly IsoequeI1ce

1 clea,rly ma'r:ked Ibedding, 2 sc,ree.s, .3 ma.1n fault·s and overthrusts, 4 subordinate fauHs and ov,eifthrust,s

B -- Litlhos't'ratigraphic sequence of the exposed Frasnian deposits and :its 'correilalt:iiolll with the seetion a10lllg !the T,ai1road cut at Kowala (after Szukzewski 1971, simplified); the Upper Frasnian sponge-bearing layers ar'e indicated

A-H - lithologic complexes; 1 s.troma,to.po,l'oid-coral liJme!stones, 2 miclritic llmestones, .3 deitrital lime'st'Oin6s, 4 nodula.r limels.toneiS, 5 mady 1imest,one .. ,

6 mar ly shales

C - Northern pairt of 'the eaS'tern 'w a1Jl , upper exploitatio:nall ~lev'€;l at the J',atZ'w:i.ca QuaTII'Y, ito show sitrOlll\gly foltded hSlpong,e-'bea:ring [Ia:y.ers Hl~2' I - lithologic comp!lexes (see 'Text-figs 2AwB).

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DICTYID HExACTlNELLto SPONGES

KI'O:x:irila'tely soo:ree' ou'bc:r6p fur SoIbolev's and Czarnocki's oollecttions) ,00 from ~~ w.OlaQuail'lI'Y (Text-'fig. 1B). The coJil..ection 'has been gathe- ed !in the years 1976-":'1980 cillierfly lfIrom Ithe NE parl of Jaiw.i.ca QualITY

~ee Text4i!g. ~} : ' '

The sponges from JaZWl:ca are (lel'ived from the greyish-reddish ~oou

:IT-marly (hllmegtones wdth a few idletr!iW mterca~ations,brachiopod coqu-

liSB 'and Madk cher'ts, W1id df ltlhe Late F':rasniiJa:n Blge (mainly Pabnato.Le- iisgjgas !Zone; oott1jplex H, otftRacki:&, ZapaSnik 197,9, oom,plex R of

~ 1001). r.r.he sponiges OCCUT clrlref[y !in 1IliOdulles and concMions weat- ,ermg 'OUit from :zn.ai1'ily beds. They are' found. in" a similwr stratigrapbi.c- fades poaii'tion in the ^iKowa~aawtcroJps, !but th,eyare 'lacking !in mOl'le J:arly or detriltal Lalte Frasnian deposits in tbis part of the aal~ice syn- lin'e (e.g. tin !the selt H otf raiil:road cut Kowalla; cf. SzulozewSikl 197,1).

ponges are 'l1ll1known ou'tside of.the Bdlechowice-iKowal'a area of ithe

~~ioe iSya1JC!Line up I1lntli~ now; even in very similar deposits of the ate F.rasnlian of the KO:elk:e area (see Sobolev 19112).

The ~ a1 J~WIiOa are 1rn.portanJt c;arnpotn;eIn!t otf the strongly Qi- ersffi.ed, 'fauna Idomlinoated ;by Ibrachiopods ,(m'aiinJly rhync:holle1lilds Pam-

~egetherhynchU8; see, Sa:rtenaer 1977), rugose ^,~bothsolitary and ,0010- lal) and !tabulate oora18; alSSocial1ield arre Styliolina, gastropods, naUlti1oikis, :miatites, IbIivalveiS, Mnoids, ? Receptaculi,tes, as well asfish!p~ates I(see aclti 1981 for preIdmina!rY !fa.unall iliis't). In !residuum nurmerous.conodonts nainly Palmatolep!is and Ancyrodella) are found.

Acknowtedgements. The authors are most grateful to Pl',afesso.:r A. Radwaii- :i for hip help ID /Pl'EIParration of the ma'IllW3croipt, and to M. Ra'Cka, M: Se. Dr. M.

arkiewicz, A. 'Pisera', JM. SIC. and Z. Be\l.ka, lM. &C. far field assistance. Thanks are

&0 due to Mrs. ID. Lis and Dr. fr. 1Za:paSnli!k for taki:ng the pboios, a1nd to 'iMrs.

Wawro !for drawing figures.

OBSERViATJONS ON THE SPONGES

SJpooimens range from smaJil ~es 1.5 to 2.5 cm across and Itall ) Ita gigantic tfoTmS 6 to 10 cm in d!ialmeter and lliearly 1'5 cm tall I~S

-2}"They range from tiny 10lW oonical Sponges that are wider than tl to iamge nearly suibcylindricall ones. A:ll have a simple,

' open:,

central 0Qg000eJ. that may be shallow and Ibl"'O'atl

m

~ to funne1-sha'Ped onges 01" deep and 'tubular in lOO1gest' cy1li.ndrical specimens. The spon- roe!, at 'the oscu1um, lis generally one ha~f to' two thirds the· diameter

the sponge. ' '

Walls are lhiJdk and pi,erc,ed by ,vertiicaaJ.y sta,cked rows of nearly

~nt~ radial, canails I(PL ,3}.Deta1ils oIf the canal patterns, 8J.'e yet be studied in sections., but both [large incuxrent and excur.rent seg- :mts are c1ea!l"ly defined in Wiea'the:red specimens and in 'the few See- ms prepared 'to date.

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1'6'6 J. KEITH lUGBY & al.

'.l1he p.rlnc.iJpa[ Slreletal net

as

a fused, rilgdd dictylid n~. P,l'leviou~ _

to

the diaoove!ry of thes:e SjpOIIl!g€S witih dictyonal nets in the Devonian of

Pol~nd and related fOl"lDS in iBelgiumi(Dean 1980; but see, aZ$o Fil'ai'POlllt lo91il) and W~ern A~ (rugiby '1979; see T,ext-fig.3),

the earliest

kr}tiwn WldouJbted hexadtinosiJels were Tremadictyon roemeri (gckleben) and Caesaria Quenstedt. These J.:altter sponges weJ.'Ie descr~bed

ft:om:

^the

TriasLsic AniSian ilower 'Welllenkrulk of Upper, Silesia (Poland), aOOOI"ding to

Rallff

^I⁽ⁱⁿAssma:nn '193(7), as _ repoo1;ed jby ,Finks '(19,67, p., 3,3'6). The dd.c:ty.tdglI'aide lis ohamcteI'ilzed /by ~. heJeacooe-based spicules tText- -fig; 413) aJIld oo!n.trasts wd,'tJh the untfI\lsed spiJcul€S of /the [yssacine grade (T'ext-fi!g.4A) or somewfh'at mOire cdmpIex lychniscid 'grade{Text-fig. 4C)

- -

in which dli'agon:alllly cross.Jbraci!ng buttresses produce, small odtahedral

lanrtern1~e strUlCtmes at spiolllle canters.

---..

/ N. - ~

I ( J,1 \

I ~\ ,~ '

1

\

. _

^...^_^-^...^..

_ - --

-,

/

I

Fig. 3. ,Model .at the positiOn elf continents in the Devonia.:nshowdng diistributdoti of _, major Late Dev,onJan ISponge 'localities ,(after ~~by 1979); -N North Pole, S

SciuthPolf. - ' - '- " '

. . ' I

H .:i:. Holy Cross Mts, R "- Rooky iMo'Un'ta.i.nsof Canada, N ...: New -YOrk- area B - Belgium, C - Canning Basm QIf Western. AustJ:alia

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ACT A GEOLOGICA POLONICA, VOL. 31 J. KEITH RTGBY & aL, FIGS 4-~

Fig. 4.. Drawlings of skeleton re].ationshijps in lyssacine (A), didyonine ,(B), and ly·chn.isciJd (C) grades Of Hexaci~nellidae (modified from Rehd 1958)

Fig. 5. Phot-omicrographs showling characteristic skeletal patter.n In the investig,atei dictyid sponges ;from ·the Upper Dev·onian ·of the Holy C.ross Mts. Light areas are either calcareous or 'moderately 'coarse cha'lcedo:ny replacing the skeleton, as seen in a horiZlo:1tal ,sectJon; dark areas are limon'i'te st.a.i'!1.s hn the matrix

A - outer ,;part od: the wall, with edge of the sponge toward the ,bottom; B - outer part ·of the wa'll, edge 0If the .sponge 'to the r,j'ght; both figures approximateoly X 25

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DICTYID BEXACTINELtnIlf sPoNGES fl67

.. .

iN~ Or' 'cenrtier\S: of ~pidules '('beX't.,f]g. 5 arid PI. 3) are spaced 0.4

to .

a:5

. n1m

a~

lli a

'tfu~h1eIiSiOrialJ.· grldwarlk. Rectangular open:i'ngs ar~ d~'t. ~.

, the

!nle,9h., aJIthoqgh 'triangular and !P01YJgonall qpenings also ^OCCUT.Rays Qf il;)e8Jms :a:re::n;llbcy~driJcall and g~er'any 0.0.4 to 0 . .06 mm in diameter. Unattacbed· mys aa-e Irare, 'a~t leaSt ,rays· :large enoUJgh to be

!PreServed

m themdderately coa:rse clla!loedony ox calcareous TeiPJ.a-

cem,ent.

A:xiaa>canals'~E{ not pr>es·erv,e'd in the spi~u1es \Cult ,in sec1iioos prepared tf;o rda'te but.:tIhere can be Ji'ttle dOUlHt lOOIlceI"n1ng the ihexad)ine base to ltIhe Ske1letan Ibecause to the ,oonsiista:nrt mesh symmetry (PI. 4).

The ~onges are U11cl'ushed

· aJna

mOi:lt hia'Vie been !f;otaUy or lParttiaa!1y

r~aced Ibysilica,generany· ohallcedany. WbeI'le silification !is coarse there is ilittile preserved of sk~ or canail detai.1s. In some specdlInens,

hOW8V,eI':, the spiomes have been :preserved as moderately fine-grained calcite. Even dill· beltter ip!I"€Sel"Vooo s,pecdIm~, deta:iils of ·ray overlap, axiia'l. canail.,s, and !p:assIilble smaJl1er s.PiOUiles are lost.

Departme11Jf; of Geology, Brigham yqun,g Utn,iversity,

ProUD, Utah 84602, PSA (J. KJetilth Rilgiby)

I7tIS,tit'Ute . of Geology, of the Silesian University,

'Ut Mielczamskiego, 41-200 S,osnowiec, Poland

(G. Raclrl, T. W:rz01ek)

DEAN J. E. 1980. Anew hexa.ctinelldd ,gpange Ifrooon the DevonJian of Belgium - A lfirst ~ccunrence. GeoZ. Soc. ,Amer. AbS'tr.acts with Programs, 12 (6), 2n.

Bou~der.

DEMBIN'SKA-ROZKowSiKA !M. 1948. ILes Zoanthai.res ,devoni.ens de ^mas.,gilfde ste- -'Cr·otix [[in Potiish with French I$'Uommary). Wfiad. MuzelUm Ziemt, 17, 187-

·220. Waxsza'Wa.

FILONOWICZP. 01973. tGeology ,af the SW-Plil"t 0If the Holy CroSs Mots ,~in PoLish].

Unpubl!ished Doctm- thelJis; !Ins'tytut Geol .. lWarszawoCl.

FINK:S R. M. 1967. Phylum ,P,orlifera Grant, 1836. \[In:) The Fossil B.e·cord, pp .. 333f-- 341. Gem. Soc.; Landon.

FR.A.IBONT C. 1911. Une iHexac'tin<elllideoo'll'Ve1:1e duDevonden !belge (Calcaire

;fu<aJsnde'n), ,pserwd.OpermmatitE?8 formarierri, g. et SIP. ID. Anm. (Mem.) 80C. Geol.

BeZgique, 38, 197;-206. tBruxelles.

GtmICH G. 1901. tNaohtra:ge zum lPalaeozoicum !des Polon£schen Mittelgebrige. N.

Jb. Geol. Miner., BeiZ Bd., 13, 33L--388. S'tu'btgart.

HALL J. & :OLA.RKIE J. iM .. 1898. A memoirOOl the iPa·laeo2lo1.c lS,Ponges cons'titu&g the :faJIDily Di:ctyospongidae. New Y()f/'k State l'vIus. Mem., 2,1-350. New y.o:rlk.

KOTiANSKI Z. 1959. Geologiical guidE/book a<n'OiSS Ilihe Holy Cross iMts (in Polish).

vo!. 1. Wyd. Qeol.; lWars·zawa.

M:A.YR J. 1929 .. lDev.o.nian .sponges af 'tihe Holy Cross lMts [inPoUS'h). Spraw. Tow.

Nauk. Lw6w, 9, 1930, 24£. iLwaw. · .

RACKa: G. 1981.. JaJtw.iJca Quamry on the Lgawa !Hill [in Polish). iP,rzewodnik: tLIIl Zjazdu Pol. Tow. Geol., Kielce.

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1618 ^J.KEITH RIGBY .to «L.

& .ZAPASNLKT. 1979. Smneremarks .,cm the tectonios of .lDevQllian rocks .. in ithe Gałęzi'L'e sy;nc'ldne ,[in PoUBh'Witn EngUsh aUmmaT1IJ. Pirzegl. Geol.,

1979 1(3), 154--4158. Warszawa.

'RAUFF II. 1937. ![In:] ,ASSM:AiN lP. Revilsion der Fauna der W,blbellosen.der oIber- - schlesioohen ,TraLs, miIt eilniem Beiltrag· ubejr die Spangien VoQIl ':tl Raufl Abh.

Prewss. ae,oZ. Land,e8aws,t., 170, 7-'-14. {Beritin. .

RIElID R. E. H. ,1958 .. A monograph dl tbe Upper Cretą.ceous Hexact:llnelUda of. Great . Briltain am.d :Norl'hern JireJand. Palaeontoor. Soc. Mo.nograph., pt. l~ 1--46.

London.

RIGBY J. rK. 1979. Pat'terns don !Devonian spcmge dislrjJbuUOOl. ,[In:] HOUSIE M. R., SQR;urrTQN C. T. &BASSiETT M. G. ~E(:ls), The Devonian System, PaEaeont.

Assoc., Spec. Pa.p. in :Pataeont., 23, 22ó-228. London.

SA:MSONawuqz J. 1952. lPale.Ozoi<: .in BalaIlid. I,n: iKSIĄZKIEwcrcz M.& SAlMiSO- NOWJCż 1.1., .An QutUnetOf geology <lif Polanki I[in Polish]. PWN; ,Wa.rrszawa.

SARTEN.AiER P. 1977. U~ naU'veau gem'e delRhyn,cbone1Ude de

'la

Ifln du Foosnden.

·Ann. Soc. GeoI. No:rd, 97 ~1), 6~76. iLilHe. .

SIEM:I:RAD2'lKII J. 1922. IGeology 'af Po1a:nd [in iPoUsh), val. 1. Muzeum im. Dzie.

. duszyckich, 2nd 00.; Lwów. . .

SOBOIEV D. 1909. iMiddl.e DeVWlda.n ol the Kielce-Sa,rrdamier:z ICha.in (in Russian].

Mat. Geol. &008., 24, 41-'-536. St. PteJ:;sbUl"g.

- ' 19110. tJ'ober dero F1und VIOOl ~berdev.cmitSlchan Schwiimmen :tn !poo.en. Zt. Dtsvh.

Geol. Ges., 62 (l), 91-92. J3er.1iln. . .

1911. Guidebook !for ge,alogicaI excurs.ton in 'the Kie1ce-Sandomierz, Chain

,[in -Russian]. Izv. Vars. PoUtechn. Inst., 1, 11-55. Warszawa.

---4 1912. iA reIIUIil"k <m the· Kielce. and RJheLn \DevIoń aOd on the te-c!tonies of

EuroPa I[tn Russian). Izv. Vars. P:oZitechn. Inst. 3, 1-18. 'Warszawa.

SZULCZEWSIKII IM. 1971. Upper DevoIJliam oonodQIlts, st.ratigraphy and :fa'Cia:l de- velopineIllt in the Haly Cro.ss :M'ts. Acta Geol. P()tOn., Z1 {1), 1-129. War-

s~wa.

I '

J. KiElTiH 1RiIGBY, !G. iRAlClK!I iT. W,RZOŁEK

WYSTĘPOWANIE GĄBEK HEXACTINELLIDA W GóRNYM DEWONIE GóR SWIĘTOKRZYSKICH

1(S'treS2lCZeme)

Z utworów g6.rnego irlllIlu synkliny gałęzjickiej(mchodnia !CZęść Gór $więto

~zyS'kich) żebrano hogatą kiolelkcję gąbak. !krzemionkowych (patrz ,fig. 1-5 OTaz pl 1--4), znanylOh ,stąd już od ·cza,sów D. S,obolewa. Gąbki te po.s.ia·dają trwały,

bocznie połqc7Jcmy szkielet typu Idikcjonmowego. T{) stanow.fs.lro, razem ^1: prawie jednoW'iekawymi li dOltąd Il1oioopr:aroowlllIly!mi Ifmmami z BelgiO. d Zachodniej Australii przenosi do dewonu dolną graniJcę 1"'ys!tępowanta rzędu Hexactinosa, znane,go do tej ipOO'Y najwcześnie'j z triasu.

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ACTA GEOLOGIC A POLONICA, VOL. 31 .r. KF.!l:'I'H RIGDY & at, PLo 1

Upper Devo'l1.i.an s,ponges rfrom the Holy Cross Mts

1.-5 - S~de views of 'oharaicteris'tic forms showing di.f.f.erent Isize, shape and surface 1>culpture; all spe'cimens fr·om the Jazwica Quar.ry except one (Fig. 5) from the Wola Qua·rry; slightly reduced

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ACTA GEOLOGICA POLONICA, VOL. 31 J. KFlITH RIGBY & aI, PLo 2

UiPlpe:r Dev,an1.a¹n sponges ;frorrn ,the J:aiwic'a Qua;nry

1· 4 - Side views of character istic forms showing different slize, shape and surface sculpture; details of canal 'Patterns are visible in Fig. 2 (magnified i.n PI. 3) and in Fig. 4 (rmagnifiied in ·PI. 4); alil natural size

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ACTA GEOLOGICA POLONICA, VOL. 31 J. KEITH RIGBY & aL, PLo 3

Details 00 'canal patterns ,O'f the ' ponge lillus'tra-te:d in PI. 2, ,F,ig. 2 (upper arrow Fig. 1, l<owe.r auow - !Fig. ;2); magn. X 5

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ACTA GEOLOGICA POLONICA, VOL. 31 J. KDtTH RIGBY &. at, PLo 4

DwtYi.d skeletal net, to show ·fused, hexactine-based spicule.s in the sponge illu- strated in ,PI. 2, Fig. 4; SEM, magn. X 40 (Fiig. 1) and X 75 (Fig. 2)