Body flattened, the two dorsal borders prominent and foliaceous.
This mode has some disadvantages attending it; such sheets are difficult to handle; the crustaceous species are liable to have their surfaces rubbed; the foliaceous species become so compressed as to lose their characteristic appearance; and the spaces between the sheets caused by the thickness of the specimen permit the entrance of dust.
I feel as if I were nearer to the vitals of the globe, for this sandy overflow is something such a foliaceous mass as the vitals of the animal body.
Head broad, surrounded by a funnel-shaped velum or hood; no radula; dorsal appendages foliaceous.
Foot broad; dorsal papillae flattened and foliaceous.