« Shell […] with pierced navel; its shape is ovate-conical; the spire is projected out and treble. It has five transversally striated whorls; about 50 rather deep furrows streak the last whorl, which expands towards the orifice and forms three quarters of the shell. The aperture is semi-oval, the columella straight; the lip, very simple, is acute. […] Only three specimens caught in Šibenik. The only species of this genus that we knew is S. costata Broc. from Novigrad. » – S. Brusina: “Conchiglie dalmate inedite”, Verhandlungen der Kaiserlich-königlichen Zoologisch-botanisch Gesellschaft in Wien Bd.15, Wien 1865, p.29-30.

Like Fossarus disciformis Granata-Grillo, Fossarus depressus Seguenza is a synonym for low-spired specimens of azoneus: « Ribless species, more depressed than the previous one [azoneus] with very wide navel. » – G. Seguenza: “Studi stratigrafici sulla formazione pliocenica dell’Italia meridionale”, Bollettino del Reale Comitato Geologico d’Italia vol.7, Firenze 1876, p.180.– 40-45m deep, Cannizzaro, Catania, E. Sicily. 4mm.

Jeffreys, about Seguenza’s Adeorbis depressus, that he seems to have observed a little more attentively than this author: « This pretty little shell, examined under a microscope, is exquisitely sculptured by close-set longitudinal folds and intermediate spiral striae, or thread-like lines. Some specimens have the whorls more or less disunited in cornucopia fashion. It seems to connect Adeorbis with Fossarus. According to the catalogue of Kleiak’s collection of Dalmatian shells his Natica crosseana is a synonym of Fossarus petitianus, Tiberi = Stomatia azonea, Brusina. » – J. G. Jeffreys: “On the Mollusca procured during the ‘Liglitning’ and ‘Porcupine’ Expeditions, 1868-70. (Part IX.)”, Proc. Zool. Soc. of London, year 1885, p.41.