The advances eggs contain larvae and have strongly pigmented, dark, often conspicuously thick walls comprising three layers,[2] and polar plugs.

[3] The structure of the egg of Huffmanela nematodes has been redescribed in great detail in 2023, with a new anatomical and terminological framework.

[3] [6][7] [8] The life cycle of Huffmanela huffmani, the only species from freshwater, has been elucidated in 2016; it includes amphipods as intermediate hosts.

[3][5] This is exceptional but perfectly valid for the International Code of Zoological Nomenclature, and eggs are considered syntypes of the new species.

Because of their polar plugs, eggs of nematodes of the genera Anatrichosoma, Capillaria or Trichuris can sometimes induce misidentifications.