Genus I. Pallene, Johnston.
Body usually very slender, distinctly divided into four segments; anterior segment usually contracted like a throat behind the insertion of the mandibles and rostrum. The rostrum is short and broad. Abdomen short, erect. The strong mandibles are placed over the rostrum, and are furnished with powerful claws; the palpi are wanting in both sexes.
The ovigerous legs are present in both sexes and are long and 10-jointed; the last four joints are furnished with a row of closely-placed toothed spines.
The legs are very long and slender, and have the 4th joint in the female considerably enlarged for the reception of the large eggs; claws furnished with large secondary claws.
The ovaries occur only in the 4th joints of all the legs but the 1st pair; and the large eggs after ejection from the genital openings are attached in pairs to the ovigerous legs. The development within the egg is very protracted, and the larvæ emerge in a nearly complete form, differing from the adults only in size, and in a few subordinate points of structure.
6. Pallene novæ-zealandiæ, n. sp. Pl. xiv., figs. 1–4.
Body slender and very smooth, with a considerable interval between the lateral processes; length 1.8 mm. The cephalic part of the cephalo-thoracic segment is considerably swollen at the insertion of the mandibles. The proboscis is stout and nearly cylindrical in form, .4 mm. in length, narrowing abruptly to the rounded extremity; mouth-aperture nearly circular. It is inserted on the ventral surface, and projects considerably downwards.
The oculiferous tubercle is short and blunt. The abdomen is short and bluntly pointed, and is directed nearly straight upwards.
The mandibles are robust and rather long; the first joint reaches a little beyond the extremity of the proboscis; the 2nd is somewhat dilated and bears a movable and a fixed claw, which are both narrow, pointed and slightly curved, and are furnished with a row of small denticles on their inner surface.
Ovigerous legs slender, 2.4 mm. long; the first three joints are short, 4th and 5th much longer, 6th only about half as long as the 5th. The four last joints are subequal in length and somewhat curved, and bear 8 (or 7) denticulated spines on their inner margins. On the last joint the spines are all of a uniform oval shape, the last one being placed quite close to the extremity of the joint. The three preceding joints have all the spines of the same oval form, except the last of each series, which is curved outwards and bears 3 or 4 long marginal teeth.
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The legs of the 3rd pair are 7°5 mm. long; the relative lengths of the joints being as follows:— 1, 2, 3, 4, 5, 6, 7,/4, 5, 16, 34, 32, 2, the 4th being much the stoutest. The 4th and 5th joints are sparingly furnished with hairs, the slender 6th joint has a considerable number. The tarsal joints and claws are normal.
Hab. Only one specimen of this elegant species was taken in Otago Harbour (27 feet) by the dredge. From its small size, I am afraid it was immature, but the great enlargement of the 4th joints of the legs would show that it was not far from sexual maturity, although no eggs were seen.