Page:Transactions NZ Institute Volume 15.djvu/122

The mouth parts are shown in position in fig. 4. In front is the labrum (a), the end of which is densely beset with fine setæ projecting radially from the tip as centre. When dissected out the labrum appears to consist of two plates each more or less triangular (fig. 6).

The mandible is strong, it bears a three-jointed appendage, second joint the longest, third fringed on one side with setæ projecting perpendicularly to the joint and increasing regularly in size towards the distal end of the joint. There is a large molar tubercle, the end of which seems to bear rows of short setæ.

The cutting end of the mandible consists of two sharp teeth, one longer than the other; below this there is a movable portion also ending in sharp teeth, and below this again a double row of strong setæ. (See fig. 5.)

The first maxilla (fig. 7) consists of two plates, the outer longer than the inner, bearing at the end strong setæ, some of which are branched, the outer edge and inner portion thickly covered with long very fine setæ; the inner lobe bears on the rounded end several long setæ, somewhat separated from each other, each plumose more especially towards the end; the distal and inner portions thickly covered with fine setæ similar to those on the outer lobe.

The second maxilla (fig. 8) consists of a stout basal portion bearing three overlapping plates: on the outer plates are long setæ, each bearing short pieces projecting at right angles to the seta. (See fig. 8a.)

On the third and inner plate are long plumose setæ, and on the inner edge of the base is a row of long plumose setæ similar to those on the inner lobe. The whole of the inner lobe, the inner portions of the two outer lobes, and some parts of the base, are covered with fine setæ similar to those on the first maxilla.

The maxillipede (fig. 9) bears at the base an irregularly rounded plate (fig. 4f) which probably is homologous with a similar plate found in Idotea and Limnoria; the basal joint is long, its inner edge towards the distal end is fringed with long plumose setæ, and there is a lobe apparently connected with the first joint; this lobe bears plumose setæ on the inner edge, and simple setæ on the outer side and distal end. The other joints of the maxillipede present nothing remarkable, and their form can be best understood from the figure.

The coxæ of all the legs can be readily seen to be simply the basal joints of the legs. In the first four pairs of legs the coxa projects slightly forwards, and is tipped with a few short setæ; in the last three pairs it projects backwards similarly. (See fig. 11.)

In the first pair of legs the distal end of the meros is produced anteriorly and is fringed with setæ, the carpus is longer than broad and