Marisa cornuarietis has escaped into the headwaters springs of the Comal and San Marcos Rivers, Texas, which contain endangered endemic fish, plants and invertebrates. The Comal also has endemic snails (Elimia comalensis) which may be at risk from Marisa and two other invasive snails -- Melanoides tuberculatus and Tarebia granifera (both commonly sold in the aquarium trade as "Malaysian Trumpet Snails"). I have also taken specimens of another "Ramshorn" Snail in the aquarium trade here -- Helisoma anceps, which is native in Texas and may be an end result of local breeders taking advantage of local ponds. P. (or H.) trivolvis is also native and about equally as common. blue austin, tx _________________________________________________________________ Keep up with high-tech trends here at "Hook'd on Technology." http://special.msn.com/msnbc/hookedontech.armx