Discoidal spumellarian species belonging to the Family Spongodiscidae and Porodiscidae float in seawater extending an axoflagellum and numerous axopodia. Observation of their skeletons by scanning electron microscopy (SEM) reveals that they possess a pore larger than openings of the spongiose meshwork in the skeleton surface. The pore is the site through which the axoflagellum projects outward and is named axoflagellum pore. This paper describes some features of the axoflagellum pore of Dictyocoryne truncatum (Ehrenberg), Spongaster tetras tetras Ehrenberg, Spongodiscus biconcavus Haeckel, and Euchitonia elegans (Ehrenberg), showing SEM photos which were taken from different view points on a single specimen. These discoidal spumellarian species float in seawater generally keeping their skeletons horizontal. The position of axoflagellum pore gives useful information on the orientation in floating. This paper draws the orientation of floating D. truncatum and E. elegans. The position and shape of axoflagellum pore differs among species, suggesting that the features of axoflagellum pore can be useful in distinguishing species and in discussing their phylogenetic relationship.