[2] In contrast to many other mollusc classes, aplacophorans have no shell, and are instead covered by aragonitic sclerites (calcareous spicules), which can be solid or hollow.

[3] The radula grows by dividing existing teeth in two, or by adding a new tooth at the center of the radular row.

[4] During development, many Solenogastres are covered by a spiny scleritome comprising spines or scale-like plates.

[5] Sclerites of Epimenia start out solid before developing a hollow stem that subsequently solidifies.

[7] Solenogastres feed on cnidaria and ctenophores, either sucking their bodily fluids or eating their tissue.