Hi Winston,

I feel better, because I also had a hard time learning that term.
It is a European term frequently used in "La Conchiglia" and such and
refers to migrant species from the Red Sea into the Mediterranean,
gradually via the Suez Canal (built by De Lesseps). This would exclude
species that become established through other man-made means such as ship
ballast water.
The term "anti-Lessepsian" refers to migration the other way around (which
seems to be much less frequent)

I have been reading about Lessepsian imigration, Lessepsian species, and
>other Lessepsians. All references are to Mediterranean shells. Someone,
>please define Lessepsian for me. My instinct tell me the meaning is
>geographical since the word is capitalized, however, I can't find
>"Lessep???" in my Atlas.
>
>Winston Barney
>Fort Worth, TX
>
>"Keep Conch-L Shell Related"

John Wolff
2640 Breezewood Dr.
Lancaster, PA 17601-4804