Treść książki
Przejdź do opcji czytnikaPrzejdź do nawigacjiPrzejdź do informacjiPrzejdź do stopki
Fig.5.Theciliaryapparatus(corona)(afterDEBEAUCHAmP1965);A-indorsalview;
B-inlateralview;
Symbols:ci-cingulum;ph-pharynx;sug-subcerebralgland;ae-apicaleye;le-lateraleye;
ce-cerebraleye;mo-mouth;br-brain;ro-retrocerebralorgan;af-apicalfield;bf-buccal
field;cc-circumapicalcilia;oe-oesophagus;tro-trochus;or-outletofretrocerebralorgan
thejuvenilesandmales.Allthecoronatypesevolvedfromacommonancestral
one(Figs5,7).
Themouthissurroundedbytheciliaryfield(thebuccalfield).Thetopof
thehead(theapicalfield)issurroundedbyacircumapicalbandofcilia.Thering
ofexternal,largerciliaiscalledthetrochus,thebandofinternalciliabeingcalled
thecingulum.Themouthislocatedbetweenthetwobands(Fig.5).
Dependingontheirmodesoffeedingandlocomotion,theMonogonontaro-
tifersmayfeatureoneofthefollowingseventypesofciliaryapparatus(Fig.7):
1.TheNotommatidaehavealargebuccalfieldwhichsurroundthemouthcavity.
Thetrochusispoorlydeveloped.Thefamilygroupscreepingorsluggishly
swimmingforms(Fig.7A,B).
2.TheAsplanchnidaefeatureastronglyreducedciliaryapparatuswhichisused
exclusivelyforlocomotion.Asinglebandofciliasurroundsalargeapicalfield
whichcarrysparsesetae;thebuccalfieldisabsent(Fig.7C).
3.TheConochilidaehaveabroadcircumapicalbeltwithastrongtrochus,horse-
shoe-shapedduetothelackofciliaontheventralside.Themouthisdorsal.
Theciliaryapparatusisusedforlocomotionandfeeding.Thistypeiscommon
inmostsessileandsomeplanktonicspecies(Fig.7D).
4.TheHexarthridaeandtheTestudinellidaeshowawell-developedcircumapical
band,astrongtrochus,andaweakcingulumwithflatlobesshapedtoresemble
shell-likewreaths.Thebuccalfieldissmall.Thistypeofcoronaistypicalof
pelagicspecieswhichuseitforfeedingandlocomotion(Fig.7E).
31
