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on the inner anterior angle of the inner joint of the last pair of pleopoda. Its function, doubtless, is to admit water to the branchial plates, and at the same time to prevent the ingress of sand or other extraneous matter, the flow of water is no doubt kept up by the movement of the branchial plates themselves.

All round the outer edge of the coxæ, the expanded joints of the antennæ and the last pair of pleopoda, two distinct parallel borders are to be seen, the outer part of the integument being apparently produced beyond the inner and more opaque parts. From the inner line numerous short setæ arise, these seldom reach much beyond the outer line. (See figs. 5 a, b, k.)

As this genus is new to New Zealand I quote here the generic characters.

"Oblong-ovate, depressed; antennæ subequal, cylindrical, not longer than the cephalon. Pereiopoda nearly alike, slender. Pleon six-jointed. Branchial plates naked. Terminal segment large, semicircular, with a lateral appendage on each side bearing two terminal slender styles."

Limnoria segnis, sp. nov. Pl. II., fig. 1.

Body covered with short setæ. Eyes large. Neither antenna longer than head, inner one stouter and longer than the outer, consisting of three joints, of which the second is the shortest, followed by a short flagellum of about three joints bearing setæ and long simple auditory cilia. Lower (outer) antennæ of four joints, the third and fourth subequal and longer than the first and second; followed by a short flagellum of three joints bearing simple setæ. Mandible strong, appendage small, apparently of only two joints, the last tipped with a few setæ. Maxillipedes similar to those of L. lignorum, but having the plate at base much longer, narrower at base than towards the distal end, extremity rounded, whole margin fringed with short setæ. Terminal segment of the tail entire rounded and flattened, without central dorsal carina and with the margins not raised. Last pleopoda with the inner branch strong, about twice as long as broad, the end and outer margin supplied with setæ about as long as the joint; outer branch small pointed at the end, and with two or three setæ on the outer edge near the end.

Length—⅙ of an inch.

Colour—white, opaque.

Hab. On seaweed, Lyttelton Harbour.

This species is very near Limnoria lignorum, the dreaded "Gribble" of Europe, but it differs in several small points already mentioned. It also differs in habits; L. lignorum burrows into the wood of piers, piles, etc.; but L. segnis I found on the roots of Macrocystis. It is very sluggish and