Iremoveanumberofcaddiswormsfromtheirsheathsandsubmitthese，astheyare，tothetestofwater。Whetherformedwhollyoffibrousremnantsorofmixedmaterials，notoneofthemfloats。
Thescabbardsmadeofshellsgotothebottomwiththeswiftnessofabitofgravel;theotherssinkgently。Iexperimentwiththeseparatematerialsonebyone。Noshellremainsonthesurface，notevenamongthePlanorbes，whichamany—whorledspiralought，onewouldthink，tokeepafloat。Thefibrousremnantsmustbedividedintotwocategories。Thefirst，darkenedbytimeandsoakedwithmoisture，sinktothebottom。Thesearethemostplentiful。Thesecond，considerablyfewerinnumber，ofmorerecentdateandlesssaturatedwithwater，floatverywell。Thegeneralresultisimmersion，asinthecaseoftheintactscabbards。Imayaddthattheanimal，whenremovedfromitstube，isalsounabletofloat。
Thenhowdoesthecaddiswormmanagetoremainonthesurfacewithoutthesupportofthegrasses，consideringthatitselfanditssheatharebothheavierthanwater？Itssecretissoonrevealed。
Iplaceafewhighanddryonasheetofblottingpaper，whichwillabsorbtheexcessofliquidunfavorabletosuccessfulobservation。
Outsideitsnaturalenvironment，theanimalmovesaboutviolentlyandrestlessly。Withitsbodyhalfoutofthescabbard，thistimecomposedentirelyoffibrousmatter，itclutcheswithitsfeetatthesupportingplane。Then，contractingitself，itdrawsthescabbardtowardsit，half—raisingitandsometimesevenmakingitassumeaverticalposition。EvensodotheBulimimovealong，liftingtheirshellastheycompleteeachcrawlingstep。