Genus Bircenna, novum.

Body broad, coxæ very shallow. Antennæ sub-equal, upper without a secondary appendage. Mandibles without an appendage. Maxillipedes with well-developed plates on both basos and ischios. Gnathopoda equal, not subchelate. Last segment of pleon and its appendages rudimentary. Telson simple, not divided.

Bircenna fulvus, sp. nov. Pl. xxi., fig. 1, a to e.

Head broad, depressed in front, antennæ short, not longer than the head; both pairs of same length, slender. Peduncle of upper not distinguishable from the flagellum, first joint about as long as the second, but stouter, third shorter than the second, flagellum of about six joints, each bearing some simple auditory cilia. Peduncle of lower antennæ with four joints distinguishable, the last as long as the two preceding, flagellum of about four joints. Both antennæ with a few small setæ. Maxillipedes short, the plates on the basos and ischios reaching to the same point and nearly to the end of the maxillipede itself. Gnathopoda equal and similar, ischios as long as meros which is rounded at the end, carpus slightly longer than the meros, expanded slightly distally, propodos slightly longer than the carpus, of same width throughout, produced very slightly at its infero-distal angle, a few small setæ on inferior margin, dactylos stout, with a tooth on inner margin, not bent back upon the propodos.

First and second pereiopoda short, meros produced at antero-distal angle. Three last pairs of pereiopoda increasing in size posteriorly, basos of each much expanded. Coxæ very shallow, broader than deep. Fourth pleopoda with rami both longer than peduncle, acutely pointed, curving upwards, one nearly twice as long as the other, fifth similar but stouter, fifth segment of pleon very short, sixth apparently absent, sixth pleopoda represented by a single joint bifid at end, outer piece rounded, inner ending in a sharp point and bearing on inner margin four or five longish setæ. Telson short, triangular, with a seta on each side near the end. Length ⅛ inch. Colour, yellow.

Hab. Lyttelton Harbour.

I do not know where to place this peculiar-looking little Amphipod; it may come near to Phlias, but the species of that genius given in the Catalogue of the Amphipoda in the British Museum are not described in sufficient detail to warrant one in forming any definite conclusion as to their relationship. I have only a very few specimens.