Having a yolk that is concentrated at one end. As in, "a telolecithal egg." Telolecital eggs have separate interior "regions," with the non-yolky stuff at one end, and the yolk at the opposite end.

The yolk mass is usually pretty large in these eggs, but stays separate from the developing embryo. The egg undergoes meroblastic or discoidal cleavage, where the yolk is not incorporated in the cells during cell division.

This odd type of egg occurs in many invertebrates and in all vertebrates lower than marsupial mammals. Usually found among fish and amphibians. It's odd, but it's not an aberration - it's natural to some species.

The word comes from the Greek lekithos, egg yolk.

thanks to
The American Heritage Dictionary at bartleby.com