They seems to be random, don't they? Is there any rhyme or reason to them?
It seems they are numbered according to when the Borg first encountered them (Kazon and Talaxians have lower designations while Earthlings and Vulcans have higher designations), yet some things disagree with this (Ferengi with a very low designation and a mention of Species 10026 in Dark Frontier -- hard to believe that the Borg have encountered 1500 species between Species 8472 and the events of VOY: DF).
Any Borg out there know the answer? Jeri?
It seems they are numbered according to when the Borg first encountered them (Kazon and Talaxians have lower designations while Earthlings and Vulcans have higher designations), yet some things disagree with this (Ferengi with a very low designation and a mention of Species 10026 in Dark Frontier -- hard to believe that the Borg have encountered 1500 species between Species 8472 and the events of VOY: DF).
Any Borg out there know the answer? Jeri?