Contribution to an inventory of the freshwater planarians of Australia and New Zealand (Platyhelminthes, Tricladida, Dugesiidae), with distribution maps of the species examined

36 Pages·2001·4.3 MB·English

by  Sluys, Ronald

Beaufortia
BULLETIN ZOOLOGICAL MUSEUM
UNIVERSITY OFAMSTERDAM
Vol. 51, no. 10 December 12,
Contribution to an inventory of the freshwater
planarians of AustraliaandNew Zealand(Platyhelminthes,
Tricladida, Dugesiidae), with distribution
maps of the species examined
RonaldSluys.*& MasaharuKawakatsu.**
Iff
InstituteforBiodiversity andEcosystem Dynamics, Zoological Museum, University ofAmsterdam,
P.O. Box 94766, 1090GTAmsterdam, TheNetherlands
**9jô chôme1-8, Shinkotoni, Kita-ku, Sapporo (Hokkaido) 001-0909,Japan
Abstract
An account is givenof 13 species offreshwater planariansfrom the familyDugesiidae, based onsamples fromnewlocali-
tiesin New ZealandandAustralia; theseinclude fournewly describedand oneproblematic species. In the caseof three
species, the material described representsthe second series ofspecimens available since the material used in the original
descriptions ofthese species, asaresult ofwhich ourunderstandingofthe morphologyof the animals can be expanded.
Inothercases,thenewmaterialalso contributedtoamoredetailedunderstanding oftheanatomyofthespecies. Thestudy
concludes with detailed distribution maps for the species examined, including not only the new distributional records
describedin the paperbutalso incorporatingall earlierrecords.
Key words:Platyhelminthes, Dugesiidae,Australia, NewZealand,taxonomy,biogeography
INTRODUCTION Recent studies have started to contribute to an
inventory of the paludicolans of these two coun-
In a recent paper Sluys (1997) highlighted our tries, with Sluys et al. (1998) describing a new
limited knowledge on the freshwater planarians species of the genus Dugesia Girard, 1850 from
of Australia, counting a meagre 22 nominal Australia, St. Clair etal. (1999) presenting a sur-
species, recorded from only a fewlocalities. The vey of the Victorian Alps, and Allison (1997)
diversity of the freshwater planarians of New reporting a new species of Spathula Nurse, 1950
Zealand may seem relatively large, considering from New Zealand.
the six species that were then known from this Over the years we have accumulated samples
much smaller landmass. However, it is obvious of freshwater planarians collected from various
thatthere is much more to be learnedabout the parts of Australiaand New Zealand. In thepre-
morphologically and phylogenetically interesting sentpaper we describe the materialof thesecol-
planarian faunaof AustraliaandNewZealand. lections, thuscontributing to, andhopefully stim-
163
ulating a future, more extensive inventory of GENUS DUGESIA GIRARD, 1850
these animals.
Dugesia notogaea Sluys &Kawakatsu, 1998
Figs. 1,49
MATERIALSAND METHODS
MATERIAL
Animals were fixed in Bouin's or Steinmann's
fluid. Some of the material not fixed in AUSTRALIA. - ZMA: VPI. 915.1,Porcupine Gorge National
Park, 70 km NE of Hughenden, north Queensland,
Steinmann'swas postfixed in this fluidbeforesec- Australia, 23-IX-1986, sagittal sections on 7 slides; VPI.
tioning. Serial sections were made at intervals of 915.2,ibid.,sagittalsections on5 slides.
7-8 |am and were stained in Delafield's hema-
toxylin anderythrosin or inMallory-Cason. DISCUSSION. - In all essential details these speci-
With respect to the samples originally con- mens correspond to the species D. notogaea. Since
tainedin Kawakatsu'sprivate collection, detailed this species was recently describedin detail(Sluys
descriptions of thecollection data, including pho- et al., 1998) we here only provide areconstruc-
tographs of the specimens, can be found in tion of the copulatory apparatus (Fig. 1),report
Kawakatsu et al. (1995a, b). In orderto facilitate differences between thepresent material and the
correct cross reference, photographs in material used for the first description of the
Kawakatsuetal. (1995b) are citedbelowwith the species, and present a more detaileddescription
plate andfigure numbersconcerned. of the various glands associated with the copula-
The material is deposited in the Queensland tory apparatus.
Museum, Brisbane (QM), the Zoological In the specimens examined the ovaries are
Museum of the University of Amsterdam much less developed than in the animals
(ZMA), the National Science Museum, Tokyo described by Sluys et al. (1998), which showed
(NSMT), or the Museum of New Zealand Te hyperplastic ovaries; in specimen VP1. 915.2
Papa Tongarewa (MNZ). ovarial tissue seems to be completely absent.
Abbreviations used in the figures: be, bursal Furthermore, ineach of the specimens only one
canal; br, brain; ca, common atrium; cb, copula- oviduct could be discerned opening at thejunc-
tory bursa; cc, clump of cells; eg1, first type of tion of bursal canal and common atrium.
cement gland; eg2, second type of cement gland; Vitellariaare well developed in bothspecimens.
cod, common oviduct; cp, ciliated pit; cpg, Thereare threetypes of gland opening into the
cyanophilic penial glands; di, diverticulum; du, atrium and/or bursal canal. A coarse-grained,
duct; e,eye; ed, ejaculatory duct; eg, erythrophilic orangesecretion is discharged into the gonopore
gland; epg, erythrophilic penial glands; fa, female and constitutes the product fromwhat is usually
atrium; gd, gonoduct; gic, genito-intestinal canal; describedas cement gland. Anequally coarse but
gl, gland; go, gonopore; in, intestine; ma, male redsecretion is discharged into theatrium imme-
atrium; od, oviduct; ov, ovary; pb, penis bulb; pg, diately dorsally to the openings of the orange
penial gland; pg1, first type of penial gland; pg2, glands and mayinvolve a second type of cement
second type of penial gland; pg3, third type of gland. A third, slightly less coarse-grained,
penial gland; ph, pharynx; pp, penis papilla; sf, cyanophilic secretion is discharged through the
sensory fossa; sg, shell gland; sp, spermatozoa; epithelium directly adjacent to theopeningof the
spe, spermatophore; sph, sphincter; sv, seminal oviduct. Most likely, this thirdtype ofgland con-
vesicle; te,testis; vd, vas deferens. cerns theshell glands, albeitthattheirsecretion is
usually of an erythrophilic nature.
Two kinds of gland are associated with the
SYSTEMATICACCOUNT
penis. A coarse-grained, orange secretion is dis-
charged intothe ejaculatory duct. A second type
Suborder TricladidaLang, 1884 of gland produces an equally coarse, purplish-
InfraorderPaludicolaHallez, 1892 bluesecretionandhasits openings in theconusof
FAMILY DUGESIIDAEBALL, 1974 the diaphragm and in the seminal vesicle. These
164
Fig. 1.Dugesianotogaea.V.P1.915.2,sagittal reconstruction ofthe copulatoryapparatus.
two typesof gland were characterized ultrastruc- slides; VP1.918.2,transverse sections on6slides; VP1.918.3,
turally by Vreys et al. (1999) forDugesia gonocepha- horizontalsections on 2 slides; VP1. 918.4,sagittal sections
la(Dugès, 1830). on 2 slides; VP1. 918.5, horizontal sections on 1 slide
(Kawakatsu et al. 1995b,PI. V, figs. C & D); V.P1. 919.1,
The copulatory bursa contains remnants of a AlderleyCreek, New SouthWales, May-June 1996,sagittal
spermatophore. sections on 2 slides; V.P1.919.2, ibid., sagittal sections on2
slides; VP1. 919.3,ibid., sagittal sections on 3 slides; VP1.
GENUS CURA STRAND, 1942 920.1,ChichesterRiver, New South Wales,January 1997,
sagittalsectionson2slides; VP1.920.2,ibid.,sagittalsections
on2slides; VP1.920.3,ibid., horizontalsectionson2slides.
Cura pinguis (Weiss, 1909)
VP1. 921.1, William River, New South Wales, January
Figs. 2, 3,51 1997,sagittal sections on3slides; VP1. 921.2,ibid.,sagittal
sections on4 slides; VP1.921.3,ibid., sagittal sections on4
MATERIAL slides; V.P1. 922.1, Cootralantra Creek, 9 km NW of
AUSTRALIA. - ZMA: VPI. 770.1, Twin Creeks, Tasmania, Berridale,NewSouthWales,5-1-1985,sagittal sections on6
sagittal sections on 2 slides; V PI. 772.1, near Brunswick slides.
Junction,Australia(33° 15'S 115°45'E),sagittal sections on NEW ZEALAND. - ZMA: VP1. 923.1, river Avon, Christ-
2 slides; V PI.772.2,sagittal sections on 1 slide;V PI.772.3, church, South Island,New Zealand, 19-1-1975,sagittal sec-
horizontalsections on 2slides; V. PI. 772.4,horizontal sec- tions on 4 slides; VP1. 923.2, ibid., sagittal sections on 3
tionson 1 slide; V PI. 772.5, transverse sectionson3slides; slides(Kawakatsuetal. 1995b,PI.VI,Fig. U);VP1.924,pre-
VP1. 916.1, MurrumbidgeeRiver, at Bredbo, 80 km S of served specimens(Kawakatsuet al. 1995b,PI.VI, figs. B&
Canberra,New SouthWales, Australia, 26-XII-1974,sagit- C), WaingaroSpring, Waingaro, 20 km Wof Hamilton,
tal sections on 5 slides; VPI. 916.2, sagittal sections on 3 North Island, NewZealand,6-VIII-1978;VP1.924.1,ibid.,
slides; VP1. 916.3,sagittal sections on 4 slides; VP1. 916.4, sagittal sections on2 slides; VP1. 924.2, transverse sections
sagittal sections on4slides;VP1.916.5,sagittalsections on3 on 3 slides; VP1. 924.3, sagittal sections on 3 slides; VP1.
slides; VP1.916.6, sagittal sections on3 slides; VP1. 916.7, 924.4, sagittal sections on2 slides; VP1. 924.5,sagittal sec-
sagittal sections on3slides; VP1.916.8,sagittal sections on3 tions on2 slides; VP1. 924.6, sagittal sections on2 slides;
slides; VP1.916.9, sagittalsections on3slides; VP1.916.10, V.P1. 925.1, at Atiamuri, 25 km SW of Rotorua, North
sagittal sections on4slides; VP1.916.11, sagittalsections on Island, New Zealand, 9-VIII-1978, sagittal sections on 2
4slides; VPI.916.12, sagittal sections on5slides; VP1.917, slides; VP1.925.2,sagittal sections on2slides (Kawakatsu et
preserved specimens (Kawakatsuet al. 1995b,PI.V,figs. P& al., 1995b, PI. VI, figs. D & E); VP1. 926, preserved speci-
Q), Mt Field National Park, SE Tasmania, Australia, 17- mens(Kawakatsu etal., 1995b,PI. VI, figs. C& H,P& Q),
VIII-1978; VPI. 917.1, ibid., sagittal sections on 2 slides; at Mairoa, 15 km SW ofTe Kuiti, near Waitomo, North
VPI.917.2,horizontalsections on3slides; V.P1.917.3,sagit- Island,NewZealand, 10-VIII-1978;VP1.926.1,ibid.,sagit-
tal sections on 3 slides; VPI. 917.4, sagittal sections on2 tal sections on 3 slides; VP1. 926.2, sagittal sections on 3
slides;V.P1.918.1,CotterRiver, 30kmWofCanberra,New slides; VP1.926.3,horizontalsections on2 slides; VP1.926.4,
South Wales, Australia,22-VIII-1978, sagittal sections on3 sagittal sections on 3 slides; VP1. 926.5,horizontal sections
165
Figs. 2, 3. Curapinguis. 2, V.P1.918,free-handsketchof living animal. 3, V.P1.927.1,sagittalreconstructionofthe copulato-
ryapparatus.
on1 slide; VP1.927,preserved specimens(Kawakatsuetal., Ball's morphological type A(Ball, 1974b:fig. 5A).
1995b,PI. VI, figs. I&J, R), at Mairoa, 15 km SW ofTe The Australian animals resemble Ball's morpho-
Kuiti,nearWaitomo,North Island, New Zealand, 10-VIII- logical typeB(Ball, 1974b:fig. 5B),albeit thatthe
912977.82;,Vtr.aPn1s.ve9r2s7e.1s,ecibtiiodn.,s soangi7ttasllidseesc;tiVonPs1.o9n274.3s,lhidoesri;zoVnPt1a.l anterior margin may beless obtusely pointed.
Animals from the Australian samples (VP1.
sections on3slides; VP1.927.4,sagittal sections on3slides.
916, VP1. 917, VP1. 918) showed large eyes set in
DISCUSSION. - Since this species has been ade- large pigment-free patches (cf. Ball, 1974b: fig.
quately described in the literature (Weiss, 1910; 5B), whereas the New Zealand specimens (sam-
Nurse, 1950; Kawakatsu, 1969a, b; Ball, 1974b) ples VP1. 924, V PI. 925, V PI. 926, V PI. 927)
and can readily be recognized, it suffices to pre- had smalleyes surroundedby small white patch-
sent here only an outline drawing of its habitus es (cf. Ball, 1974b:fig. 5A). Ball (1974b) observed
and reconstruction of the copulatory apparatus both morphological types from one locality, viz.
(Figs. 2, 3) andto discuss some minor différences New South Wales. He was not able to correlate
betweenour observations and those of previous the external features of the animals with any
workers. anatomical differences, which corresponds with
Some differences in external morphology our findings.
could be observed between animals from Nurse(1950) reported awidecommon oviduct
Australia and New Zealand. The head of New but Kawakatsu (1969b) reported a very short
Zealandspecimens is of alowertriangular shape common oviduct. However, after examination of
as compared withAustralian animals, resembling the material presented in the present study, we
166
find the situation more in agreement with the Thepenial papilla is a rather stout, cylindrical
account of Weiss (1910), who described the two structure with averyblunt tip; itis covered witha
oviducts as separately opening into the bursal cuboidal, nucleate epithelium that is underlain
canal, close to the point where the canal sharply with a layer of circular and longitudinal muscle.
bendsanteriad. Thepenis papilla projects intoboththe maleand
the common atrium, which are separated from
Cura fortis n.sp. each other by a constriction. The maleatrium is
Figs. 4-6, 51 lined with tall, nucleate cells, whereas the com-
mon atrium is lined with a very flat, nucleate
MATERIAL epithelium. The gonoporeis locatedat the mid-
Holotype: MNZ ZW 1495,nearWellington, North Island, ventralportion of the commonatrium.
NEWZEALAND, 1-1-1975,sagittalsections on 12slides. Themid-dorsalsection of the commonatrium
receives the opening of the bursal canal, which
DIAGNOSIS. - Curafortis n.sp. can be distinguished receives theerythrophilic secretionofshell glands
from its congeners by its numerous dorsal testes nearthe opening. Thebursal canalis linedwitha
that extendbackwards to the level of the mouth, nucleateepitheliumandis provided withasubep-
arelatively voluminouspenial papilla, a gonopore ithelial layer of longitudinal muscle and a well
locatedin themiddleof thecommonatrium, and developed layer of circular muscle. The bursal
reversed bursalcanal musculature. canal communicates with a relatively small,
roundedcopulatory bursa.
ECOLOGYAND DISTRIBUTION.- Knownonly from Theovaries are poorly developed in the speci-
the type locality, anarrow river nearWellington. men examined, being located at about 700 (am
behindthebrain. Although oviducts couldbe dis-
ETYMOLOGY. - The specific epithet is derived cernedin the prepharyngeal partof the animal,
from the Latin adjective fortis, meaning 'firm', notraces of the ducts are visible in the posterior
and alludes to the large penial papilla, as com- section; consequently, there is no information on
pared withother species ofCura. theopeningsof theoviducts into thebursal canal.
DESCRIPTION. - Preserved up to 8 X 3.5 mm. COMPARATIVEDISCUSSION. - Sluys (1997) restrict-
Dorsal surface dark brown, in some specimens ed thegenusCura to the species C. pinguis (Weiss,
slighdy reddish; ventralsurface with dark greyish 1909), C. foremanii (Girard, 1852), and C. graffi
ground colourand many blackish spots. Sensory (Weiss, 1909). The last-mentioned species is
spots were not observed, neitherinthe intactani- known only from its original description, based
mals nor in the sections (Fig. 4). Eyes set in pig- on two not fully mature specimens, andwas only
ment-free patches. tentatively assigned to the genus Cura since it
Pharynx located in the middle of the body; couldbelong also to the genus GirardiaBall, 1974
mouthopening at the posterior end of the pha- (because of theabsence of a doubleseminal vesi-
ryngeal pocket. cle, it is unlikely thatC. graffibelongs to the genus
Relatively small testes located dorsally, extend- SchmidteaBall, 1974).
ing fromaconsiderabledistancebehindthebrain The grossmorphology of thecopulatory com-
to the level of themouth (Fig. 5). plex of C. graffi is rather differentfrom thatof C.
The vasa deferentia penetrate separately the fortisn.sp. andprecludes any synonymyof thetwo
penis bulb, within which they unite to form the species. The species C. pinguis, C.foremanii, and C.
ejaculatory duct. Thelatter is aratherwide duct, fortis n.sp., however, are very similar in the gross
linedwith a nucleate epithelium, opening at the morphology of the copulatory apparatus. The
tip of the penial papilla. The ejaculatory duct most characteristic features, in this respect, are
receives the openings of penis glands over its the finger- or thumb-shaped penial papilla, and
entire length, while there is a particularly dense theopening of thebursal canalinto themid-dor-
accumulation of secretion at thedistal partof the sal or even antero-dorsal sectionof the common
duct, near the tipof the penial papilla (Fig. 6). atrium. As a result of the taxonomic restriction
167
Figs. 4-6.Curafortisn.sp.4,ZW 1495,sketchofpreserved specimen. 5,ZW1495,sagittalsection.6, ZW1495,sagittalrecon-
structionofthe copulatory apparatus.
mentionedabove, for the first time in its complex InC.foremanii and C. pinguis there are very few
history (cf. Ball, 1974b) the genus now has prepharyngeal testes, located dorsally in the for-
attained somemorphological unity. mer and ventrally in the latter, thus contrasting
168
Figs. 7, 8. Spathula schauinslandi.7, free-hand sketch living animal. 8, V.P1.929.1, sagittalreconstruction of the copulatory
apparatus.
with thesituation inC.fortis n.sp. (with numerous the clade comprising all dugesiid genera,except
dorsaltestes betweenthe ovaries and the mouth). Cura, Girardia and Schmidtea. However, it should
,
Other differencesconcern theshape of thepenial benotedthatthecharacterof the reversedbursal
papilla, the location of the gonopore,and the canal musculature is not a strict synapomorphy,
musculature of the bursal canal. InC.fortis n.sp. since there are component species of the clade
the penial papilla is thumb-shaped, whereas the that have a non-reversed musculature(cf. Sluys,
papillae of C.pinguis and C.foremanii are thinner 2001).
and more finger-shaped. In C. fortis n.sp. the
gonoporeis locatedinthemiddleofthe common GENUS SPATHULANURSE, 1950
atrium, whereas in C. pinguis and C.foremanii the
gonoporeoccupies a more usual position at the Spathula schauinslandi (Neppi, 1904)
posterior end of the atrium. Figs. 7, 8, 51
In recent phylogenetic analyses of the
Dugesiidae (Sluys, 1997, 2001) a reversed bursal MATERIAL
canal musculaturewas postulated as an apomor- NEW ZEALAND. - ZMA VP1. 929, preserved specimens
phy forallgeneraof the family, except Schmidtea, (Kawakatsu et al. 1995b, Pl. VI, figs. N & 0), Waioura,
Kaimanawa mountains, North Island, New Zealand, 11-
Girardia, and Cura. Thenon-reversed condition is
VIII- 1978;VP1.929.1,ibid.,sagittal sections on2slides.
present in C. pinguis and C.foremanii and hasbeen
describedalso forC.graffi, although thereremains DESCRIPTION. - Live specimens 15-20 mm long
some uncertainty aboutthe correctness of Weiss' and 1 mm wide (Fig. 7). Head truncated, with
(1910) observationson thelast-mentioned species blunt auricles. Dorsal surface dark brown or
(Sluys, 1997). The assignment of the species C. blackish; ventralsurface greyish.
fortis n.sp. to the genus Cura introduces a case of Thepharynx measures aboutone-fourthof the
parallelism forthe reversedbursal canalmuscula- bodylength inpreserved specimens; mouthopen-
ture,acharacterthatis nownolonger confinedto ing locatedat theposteriorendof thepharyngeal
169
cavity. cyanophilic glands, whereasin our material these
In the postpharyngeal region of the body the glands are of an erythrophilic nature.
large testicular follicles are situated ventrally but
intheprepharyngeal partof thebody thefollicles Spathula limicolaNurse, 1950
occupy most of the dorso-ventral space. The Figs. 9-12, 51
testes extend from directly behind the ovaries to
the tail.
In theposterior partof the body, thevasa def- MATERIAL
erentia expand to form spermiducal vesicles, NEW ZEALAND. - ZMA: VP1. 930, Omara Stream,
Omarama, South Island, New Zealand, 22-11-1998, pre-
which narrow considerably before penetrating served specimens; VP1. 930.1, ibid., sagittal sections on 3
the penial bulb and separately opening into the slides; VP1. 930.2,ibid., sagittal sections on3 slides; VP1.
proximal sectionof theejaculatory duct. Thelat- 930.3,ibid.,sagittal sections on3 slides;VP1.930.4, sagittal
ter is an irregularly shaped duct, lined with a sections on3slides.
nucleate epithelium, opening at the tip of the
penial papilla (Fig. 8). DESCRIPTION. - Maximum length of living ani-
Very extensive glands discharge a finely granu- mals8mm. Headspathulate. Dorsalsurface light
lar, erythrophilic secretioninto the proximal sec- brown, with paler area on head(Fig. 9). Eyes in
tion of the ejaculatory duct. The cell bodies of pigment-free patches. Small number of sensory
theseglands are located welloutsideand dorsally fossae atanterior margin; ciliated pits absent.
of the penis bulb. Another, morecoarse-grained Pharynx situated in the posterior half of the
erythrophilic secretion is discharged into parts of body; mouth opening at the posterior endof the
the more distal section of the ejaculatory duct pharyngeal pocket.
and through the covering, nucleateepithelium of The rather small testes are situated ventrally
the penial papilla. and extend from directly behind the ovaries to
Thepaired ovaries are locatedat somedistance thelevelof themouthor, occasionally, to thelevel
behind the brain. Posterior to the gonopore the of the copulatory apparatus.
oviducts give off a medially directedbranch that Thevasa deferentiaare expanded to spermid-
opens laterally into the ventral, proximal section ucal vesicles. Within the penial bulb thevasa def-
of the bursal canal; the oviducts extend towards erentia uniteto form a very short commonduct
the tail. Ectally to the openings of the oviducts, that opens through the antero-dorsal wall of the
the bursal canal receives the erythrophilic secre- intrabulbar seminal vesicle, the latter communi-
tion of shell glands. cating with the ejaculatory duct, which opens at
The bursal canal is lined with a nucleate the tip of the short, conical penial papilla.
epithelium and is covered with a subepithelial Seminal vesicle and ejaculatory duct are lined
layer of longitudinal muscle and alayer of circu- with a rather tall, nucleate epithelium and are
lar muscle, consecutively; the canal communi- surroundedby alayer of circular muscle.
cates with asac-shaped copulatory bursa. Three distinct regions can be distinguished in
thepenial lumen, i.e. the combinedseminal vesi-
DISCUSSION. - The anatomy of the specimen cle and ejaculatory duct: an expanded proximal
described above resembles closely the material section (the vesicle), anarrow middle section, and
described by Neppi (1904) and Ball (1977) and asomewhatexpanded distalsection(Figs. 10-12).
therefore there cannot be any doubt about the These parts are distinguishable on thebasis of (1)
identity of this specimen. The external appear- different types of secretion that are discharged
ance of our animal, however, differs from thesit- through their lining epithelium, and (2) more or
uation describedby Ball(1977), who reported for less pronounced constrictions between the sec-
living animals ablundy triangular headwith dis- tions. The seminal vesicle and the distal section
tinct auricles, more or less similar to the head receive weakly staining erythrophilic secretions,
shape of European Ijimia felina (Dalyell, 1814). probably originating from different types of
Furthermore, according toNeppi (1904) andBall gland. The middle section receives an equally
(1977) theseminal vesicle receives theopenings of faintly staining cyanophilic secretion.
170
Figs. 9-12.Spathulalimicola. 9, V.P1.930,free-hand sketch ofhead oflivinganimal. 10,V.P1.930.1,sagittalreconstructionof
the male copulatory apparatus. 11 (page 172), V.P1. 930.1,sagittal reconstructionofthe femalecopulatory apparatus. 12
(page 172), V.P1.930.4,sagittalreconstructionofthecopulatoryapparatus.
Thepenialpapilla, whichiscovered by anucle- bursa is rather small and lined with a rather tall
ate epithelium, almost entirely fills the maleatri- epithelium. However, in other specimens (e.g.
um. Through a narrow passage the male atrium specimen VP1. 930.4; Fig. 12) thebursa is great-
communicateswith thebursal canaland the gon- lyexpanded andhas a highlyreducedepithelium;
oduct leading to thegonopore. in these specimens the bursa contains clumps of
The paired ovaries are situated directly behind spermand remnants of aspermatophore.
thebrain. Theoviducts run far into theposterior
end of the body, giving off a medially directed DISCUSSION. - The specimens are assigned to the
branchjust posterior to thelevel of thegonopore. genus Spathula mainly on the basis of their
These medially running oviducal branches open spathulate head and possession of branched
separately into the bursal canal. oviducts. In addition to branched oviducts, most
Thebursal canal is linedwith awelldeveloped species of Spathula are characterized also by the
nucleate epithelium with prominent cilia and is presence ofciliated pits. S. limicola was described
surroundedby a subepithelial layer of longitudi- with ciliated pits (Ball, 1977) but these structures
nalmuscle, followedby a layerof circular muscle. appeared tobe absentin theOmara stream spec-
Ectally or ventrally to the openings of the imens. Ball (1977) argued that the apparent
oviducts, thebursal canalreceives theopenings of absence of sensory fossae in S. limicola might be
theabundanterythrophilic shell glands. Thebur- theresult of thepoorhistological conditionof the
sal canalcommunicates witha sac-shaped copu- type material thathe examined; Dr F. R. Allison
latory bursa. Inspecimen VP1. 930.1 (Fig. 11) the (née Nurse) (in litt.) recently confirmed that the
171
Figs. 11,12.Forlegends, seepage 171.
172