A long-dead race, whose bodies were based on silicon rather than carbon. When they realized that their race was on the verge of extinction, they built a number of seed carriers, containing all the chemicals and information required to restart their race on another suitable planet, as well as all their histories and technical knowledge.
Unfortunately, their attempt failed as all the carriers were lost, and the race was doomed to extinction.
HOMEWORLD - Unknown
FIRST APPEARED - Remnants
Remnants - An alien device is discovered on the seabed near Atlantis.