Athenaria (Abasilaria) with usually elongate body and with the proximal end physa-shaped, rarely flattened. Column sometimes without regional differentiation sometimes divisible into physa, scapus and scapulus. No sphincter. Tentacles few up to about 40, the inner not shorter than the outer ones. A single siphonoglyph or no distinct ones. Perfect pairs of mesenteries variable in number up to 20. Retractors of the perfect mesenteries strong, diffuse to restricted, more or less reniform. Parietal muscles distinct.
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1