There are a pair of ringed antennæ projecting from the anterior end of the head, and a pair of simple eyes, placed on the dorsal surface at the roots of the antennæ.
The appendages of the body behind the antennæ are disposed in twenty pairs.
1. The single pair of jaws placed within the buccal cavity in front of the true mouth opening, and consisting each of a papilla, armed at its termination with two cutting blades.
2. The oral papillæ placed on each side of the mouth. At their apices the ducts of the slime glands open.
3. The seventeen pairs of ambulatory appendages, each provided with a pair of chitinous claws at its extremity.
4. The anal papillæ placed on each side of the generative opening.
Colour.—The following statements on this head are derived from observations of spirit specimens. The colour varies in different individuals. It always consists of a groundwork of green and bluish grey, with a greater or less admixture of brown. The chief variations in the appearance of the animal, so far as colour is concerned, depend on the shade of the green. In some it is dark, as in the specimen figured (fig. 1); in others it is of a lighter shade.
There is present in most specimens a fairly broad light band on each side of the body, immediately dorsal to the attachment of the legs. This band is more prominent in the lighter coloured varieties than in the dark, and is especially conspicuous in large individuals. It is due to a diminution in the green pigment, and an increase in the brown.
There is a dark line running down the middle of the dorsal surface, in the middle of which is a fine whitish line.
The ventral surface is almost entirely free from the green pigment, but possesses a certain amount of light brown. This brown pigment is more conspicuous and of a darker shade on the spinous pads of the foot.