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1)inmostspecies,themaleimpregnatesthefemalebypiercingherloricawith
thecopulatoryapparatus.Themalecrawlsonthefemalebodyand,having
locatedthethinnestspotonthelorica,boresthroughitandinjectsthesperm
intothebodycavity,thensubsequentlyleavesthefemaleandperishes;
2)insomeAsplanchnaspecies,matinginvolvesintroductionofthecopulatory
apparatusintothefemalecloacaandinjectionofthespermintothefemale
pseudocoel.
Rotiferspermatozoidsbelongtoeitherofthefollowingtwotypes:
1)typical,withovalorsphericalheadsandmoreorlessdistincttailsequippedby
athinfilament;thetypicalspermatozoidsvaryinsize,from4uminFiliniato
40-60uminLacinularia.
2)non-typicalspermatozoids,locatedinmostcasesinthedistalpartofthesperm
duct;suchspermatozoidswerediscoveredinalmostallspeciesofthesuper-
ordersGnesiotrochaandPseudotrocha.Thespermatozoidsaredistinctlyrod-
shapedorrhomboidandusuallylackanywell-developedhead.Theheadislost
duringthedevelopment,wherebytheresultantspermatozoidsareequivalentto
thetailpartofthetypicalspermatozoids.Someauthorsregardthemasfunc-
tioningmainlyasadevicewithwhichtoborethroughthefemalebodycover.
Anhydrobiosis.Itisaspecialkindofanabiosisthatinvolveslossofall
themoisturefromthebodyviaevaporationandoccursinbdelloidrotifers.Itis
astateofthemaximummetabolicarrestwhichrequiresspecialadaptations(RICCI
1998).Thereisnoinformationastohowthemetabolismbecomesstabilisedin
thosedesiccatedanimals;however,theyhavebeenshowntocontainhighcon-
centrationsoftrachylose.Itseemsthattrachylose,asaccharidederivative,isan
importantagentthatstabiliseswaterlossinbdelloids(RICCI1987).Similarlyto
someotheranimals,anhydrobioticrotifers-inadditiontohavingtheirmetabo-
lismreducedtotheminimum-loseallunboundwaterfromthebodyandsurround
itbyathickshell.Similarlytotheirdormanteggs,adultanhydrobioticfemales
areveryresistanttoadverseenvironmentalconditions(oxygendeficiency,lackof
water,changesinambienttemperature,salinity).However,thereisadangerthat
cannotbealwayssafelyterminated:toolongaperiodofdesiccationmaybefatal
forarotifer.Rotifershavebeenobservedtosuccessfullyterminateanhydrobiosis
thatlastedseveralmonthstoayear.However,thelongerthedesiccation,thehigh-
erproportionofanhydrobioticindividualswereunabletosuccessfullyterminate
anhydrobiosisandresumenormallifefunctions.
Mniobiamagna,havingstayedinanhydrobiosisfor2.5years,wasobserved
toresumenormallifefunctionswithin80-90minutes.Thelongestanhydrobiosis
(59years)wasreportedbyRAHm(1923)(quotedbyGILBERT1974)fromMacro-
trachelaquadricorniferafoundinmosseskeptinaherbary.However,thosedata
arenotfullyreliable,asRAHmsuspectedthattherestingstagescouldhavebeen
transferredtotheoldmossesfromspecimenscollectedlater.
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