Thinking that Mr. Kirk's specimens might possibly belong to the same species as those I had taken at Lyttelton I wrote to him about them, and in reply he very kindly sent me the three specimens for comparison. I have examined these as carefully as possible, and though they differ in some respects from my Lyttelton specimens and from Mr. Haswell's description—approaching somewhat more nearly to P. cylindricus, Say—still I am convinced that they belong to the same species, and that although it is very near to P. cylindricus, Say, it is advisable to consider it as distinct until a comparison of actual specimens of the two can be made.

Mr. Kirk's three specimens were all very much larger than mine; the largest was .56 of an inch in length of body, while my largest specimen is only .12 inch; Mr. Haswell gives the length of his specimens as “about ¼ inch.” The inferior antennæ, as in my specimens, and as shown in Mr. Haswell's figure, are about half the length of the body, not more; in P. cylindricus they are “more than half the length of the body.” The length of the upper antenna compared with that of the lower varied somewhat. In the first specimen it reached to about the middle of the flagellum, in the second only to the end of the peduncle, in the third specimen the lower antennæ were broken off. In my specimens also this character varies, usually, however, the upper antenna reaches to the end of peduncle of lower; with regard to his specimens Mr. Haswell says:—“Inferior antennæ stout, subpediform, with the peduncle equal in length to the superior pair.”

All three specimens had the flagellum of lower antenna as long, or very nearly as long, as the last joint of peduncle; in my specimens and in Mr. Haswell's it is as long, and thus differs from P. cylindricus where it is “scarcely half the length of last joint of peduncle.”

In Mr. Kirk's specimens, as in mine and Mr. Haswell's, the spines found on the end of the lower antenna are only somewhat curved, not hooked, as in P. cylindricus. The inner margin of the finger of the first gnathopod was, as in P. cylindricus, “serrated, almost pectinated;” this is, to a less degree, also the case with my specimens of the male, in the female it is somewhat roughened only. The Wellington and Lyttelton specimens and Mr. Haswell's agree in having the propodos of the second gnathopod longer than in P. cylindricus; it is longer than the cephalon and first two segments of pereion. The finger in all has the inner margin smooth, in P. cylindricus it is “coarsely serrated.” The finger has an enlargement on the inner margin near its base, in Mr. Kirk's specimens the apex of this enlargement is rounded, in mine it is more pointed, and the enlargement is nearer the base of the finger; it is not mentioned by Mr. Haswell. My specimens agree with Mr. Haswell's in having “a blunt tooth at the proximal and another at the distal end of the concave border” of the propodos of the

second gnathopod; both are wanting in P. cylindricus; in Mr. Kirk's specimens the one at the distal end is present, but the proximal end is simply rounded as in P. cylindricus. In Mr. Kirk's specimens, as in some of mine, the outer branch of the last pleopod terminates in more than three teeth, four, five, and even six are found. P. cylindricus is described as terminating “in three hooks.” I do not, however, attach any importance to this, for it is evidently a character that varies with the size and age of the specimen.

The general description of this species will be as follows:—

Podocerus longimanus. Pl. xvii., fig. 2, a to e.

Podocerus cylindricus, Kirk. Trans. N.Z. Inst., vol. xi., p. 402. (Not Say.).

Wyvillea longimanus, Haswell. Proc. Linn. Soc. N.S.W., vol. iv., p. 336, pl. 22, fig. 7.

Male.—Eyes round. Superior antennæ about as long as the cephalon and first three segments of the pereion; first segment of the peduncle short, thick; second and third much slenderer, second slightly longer than the third; secondary appendage slender, 2-jointed, nearly one-fourth the length of flagellum; flagellum rather longer than last joint of peduncle. Inferior antenna about half the length of the body, stout, subpediform, peduncle equal in length to the superior antenna; flagellum as long as the last joint of peduncle, armed towards the end with stout curved spines. Both antennæ having the inferior margins fringed with long setæ.

First pair of gnathopoda small; carpus nearly as broad as propodos and about half as long; propodos ovoid with two stout setæ at the point where the dactylos impinges, palm with a few setæ; dactylos with concave margin more or less serrated, almost pectinated in large well-developed specimens. Second gnathopoda very large, carpus very short, propodos longer than the cephalon and first two segments of the pereion, cylindrical, sides parallel, curved, a blunt tooth at the distal end of concave margin, proximal end rounded or produced into blunt tooth; palm broad, more or less thickly fringed with fine setæ. Dactylos nearly as long as the propodos, concave border smooth, with an enlargement near the base. Posterior pleopoda with the peduncle elongated, narrowing slightly towards the end, upper margin with a few short setæ; rami very short, inner styliform, outer ending in from 3 to 6 upturned teeth. Telson conical, blunt.

Female.—Differs from the above in having the concave margin of finger of first gnathopod only slightly roughened, not serrated. Second gnathopod not larger than the first, similar to it in shape, but with the carpus shorter, and propodos rather more narrowed distally. Dactylos with basal half of concave margin roughened, extremity smooth.

Colour, pale yellow, more or less thickly covered with black dots and markings.

Length of largest specimen .56 inch.

Hab. Lyttelton Harbour; Worser Bay, Wellington (T. W. Kirk); Port Jackson (W. A. Haswell).

The differences between this species and Podocerus cylindricus, Say, have already been mentioned in the general comparison of specimens from the different localities; but for the sake of greater clearness I will recapitulate them.

Flagellum of lower antenna is as long, or very nearly as long, as the last joint of peduncle, the stout spines found on the end of it are not developed into hooks. The inner margin of dactylos of first gnathopod is only roughened in the female, and in the male the serrations, though sometimes as great as in P. cylindricus, vary. The second gnathopod is larger than in P. cylindricus, and is much larger in the male than in the female. In P. cylindricus the female differs from the male only in “the slightly smaller size of the propodos of second pair gnathopoda;” the second gnathopod of female also differs considerably in shape from that of the male. There is a blunt tooth at the distal end of the concave margin of propodos (of male); not found in P. cylindricus. The concave margin of the dactylos is smooth in the male, in female roughened on proximal part only.

These differences, though somewhat numerous, are none of them of very great importance; and, if P. cylindricus varies as much as P. longimanus, I dare say it would be difficult to find constant differences of any importance between the two species. In considering the question it must be remembered that there are other similar cases: Paranthura costana, Philougria rosea, Lysianassa magellanica, Pinnotheres pisum, etc.: this, however, is not the place to discuss the general question of the occurrence of the same species in both the northern and the southern seas.

Note.—My reasons for considering the two animals described above as male and female of the same species are these:—(1) They resemble one another so closely in everything but the gnathopoda that they must be considered as belonging to the same species; (2) the form with the small gnathopoda is certainly a female, for I have frequently seen specimens carrying eggs; (3) the form with the large gnathopoda I have never seen bearing eggs.

The large gnathopoda of the male are only possessed by fully-grown specimens. In very young animals they are more like those of the female, having the palm extending only about half way along the inferior edge of the propodos and defined by two or three stout setæ. In slightly older specimens the palm is longer, until it extends along the whole length of the margin of the propodos, and finally the setæ are cast off and the gnathopod assumes the form already described.