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 setae 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 setae 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 setae. 



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 setae. (See fig. 5.) 



The first maxilla (fig. 7) consists of two, plates, the outer longer than 

 the inner, bearing at the end strong setae, some of which are branched, the 

 outer edge and inner portion thickly covered with long very fine setae ; the 

 inner lobe bears on the rounded end several long seta?, somewhat separated 

 from each other, each plumose more especially towards the end ; the distal 

 and inner portions thickly covered with fine setae 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 setae, each bearing 

 short pieces projecting at right angles to the seta. (See fig. 8a.) 



On the third and inner plate are long plumose setae, and on the inner 

 edge of the base is a row of long plumose setae 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 setae similar to those 

 on the first maxilla. 



The maxillipede (fig. 9) bears at the base an irregularly rounded plate 

 (fig. 4/) 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 setae, and there is a lobe apparently con- 

 nected with the first joint ; this lobe bears plumose setae on the inner edge, 

 and simple setae 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 coxae 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 for- 

 wards, and is tipped with a few short setae; 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 setae, the carpus is longer than broad and 



