« Body sub-orbicular, depressed, convex above. The superior lamina is yellowish, sprinkled with bright brimstone colour, and marked with round pustules interspersed with a few black spots. In the front is a sinus. Tentacula two, long and filiform, placed one on each side the front of the head. Eyes two, black, situated at the base of the tentacula on the outside, but usually concealed by the anterior margin of the superior lamina; they are however sufficiently conspicuous on the under side of the animal by reason of the transparency of that part. The inferior lamina or sustentaculum is ovate, attenuated at the posterior end, projecting a little beyond the shield or upper lamina, when the animal is in progressive motion, but vhich conceals the head or anterior part, except about three-fourths of the tentacula. » – op. cit. p.186.