Guide to Mastogloia

The valves of Mastogloia are elliptic to elliptic-lanceolate or lanceolate, with rounded to capitate ends. The valvocopula (first girdle band) each possess complex silica chambers, called partecta, that function to secrete strands of mucilage. The raphe is straight or undulate. The axial area is narrow, with a slightly expanded central area. Living cells have two plastids.

Mastogloia is primarily a marine genus. A few species are found in inland waters, typically in benthic habitats. The genus appears to be closely related to Aneumastus, based on a similar, but less complex, valvocopula.