90 Transactions.—Zoology. 
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 sete 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 sete 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 setze. 
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 sete. (See fig. 5.) 
The first maxilla (fig. 7) consists of two plates, the outer longer than 
the inner, bearing at the end strong sete, some of which are branched, the 
outer edge and inner portion thickly covered with long very fine setze ; the 
inner lobe bears on the rounded end several long sete, somewhat separated 
from each other, each plumose more especially towards the end ; the distal 
and inner portions thickly covered with fine sete 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 sets, each bearing 
short pieces projecting at right angles to the seta. (See fig. 8a.) 
On the third and inner plate are long plumose sete, and on the inner 
edge of the base is a row of long plumose sete 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 sete similar to those 
on the first maxilla. 
The maxillipede (fig. 9) bears at the base an irregularly rounded plate 
(fig. 4 f) which probably is homologous with a similar plate found in Jdotea 
and Limnoria ; the basal joint is long, its inner edge towards the distal 
end is fringed with long plumose sete, and there is a lobe apparently con- 
nected with the first joint; this lobe bears plumose sete on the inner edge, 
and simple sete on the outer side and distal end. The other joints of the 
maxillipede present nothing remarkable, and their form can be best under- 
stood from the figure. 
The coxe of all the legs can be readily seen to be simply the basal joints 
ofthelegs. In the first four pairs of legs the coxa projects slightly for- 
wards, and is tipped with a few short sete; 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 sete, the carpus is longer than broad and 
