from:
http://www.privatehenrykalinowski.org/Sea_Bag/Shellback/shellback.html
"Other Shellback* certificates include the Gold Shellback title for crossing at the International Date Line and the Emerald Shellback title for crossing at the Greenwich Meridian."
* Shellbacks are sometimes called (Sons of Neptune).
from wiki-waki:
http://en.wikipedia.org/wiki/Line-crossing_ceremony
Similar "fraternities" in the navy include:
* The Order of the Blue Nose for sailors who have crossed the Arctic Circle.
* The Order of the Polar Bear for U.S. sailors who have crossed the Arctic Circle.
* The Order of the Red Nose for sailors who have crossed the Antarctic Circle.
* The Order of the Golden Dragon for sailors who have crossed the International Date Line.
* The Order of the Ditch for sailors who have passed through the Panama Canal.
* The Order of the Rock for sailors who have transited the Strait of Gibraltar.
* The Safari to Suez for sailors who have passed through the Suez Canal.
* The Royal Diamond Shellback for sailors who cross at 0 0 degrees off the coast of West Africa (where the equator crosses the Prime Meridian)
* The Realm of the Czars for sailors who crossed into the Black Sea.
* The Order of Magellan for sailors who circumnavigated the Earth.
Jon, trusty shellback since 1987