ISOPODA. 
57 
about half the length of the third and forms a bend in the direction of the appendage. 
The two terminal ones are large and slender, the distal one being a little the longest. 
The peduncle bears numerous scattered setse. The flagellum is scarcely as large as the 
two terminal joints of the peduncle. 
The mandible is curved and rather tapering, it terminates in a cutting edge with 
two stout teeth, one of which, the lower one, is lobed; below these teeth are four or 
five spines which have their distal portions converted on one side into a thin finely 
serrated blade. The molar process which arises from the base of the organ, and is 
almost as large, is slightly constricted in the middle ; the distal extremity is strong 
and has a curved process or tooth anteriorly. The palp is a comparatively delicate 
structure of three joints, the proximal two are subequal in length, the third is little 
more than half as long and terminates in a pectinate claw. 
Both pair of maxillae are quite normal. 
The maxilliped (fig. 3a) is also normal in structure, the straight inner edge of the 
masticatory lobe bears two papilliform teeth, the distal extremity is straight and armed 
with setae, three at least of these below the edge are broad and finely denticulate, 
exactly like the denticulate spines on the ovigers of so many Pycnogonids, the others 
are simple. The outer margin is rounded to some extent. The palp is five-jointed, 
the second joint being by a little the largest. The first three are broad and the two 
large ones have a few long setae on their inner margin, and the other two joints are 
cylindrical with setae distally. The epignath is large, rather more than three-quarters 
the length of the entire masticatory lobe, it is somewhat conical in shape, attached at 
the inner lower angle. 
Pereiopoda. The first pair are short and stout, here the basis is long and 
cylindrical, the ischium is just half the length, the merus about half this, but 
enlarged dorso-ventrally and with set® distally. The carpus is about half as long 
again as the merus, swollen ventrally and armed with three stout teeth and the 
stumps of one or two more. The propodus is rather short, stout and curved and bears 
several setae, the stronger ones are ventral. The dactylus is long, slender, and has 
an accessory claw. 
In the remaining pereiopoda the joints vary a little in their proportions, but 
there are no structural differences between them. All the joints are cylindrical 
except the merus, which is swollen dorsally. The carpus is elongated and armed 
ventrally with three or four spinous setse. The propodus is curved slightly and 
carries a few strong setae dorsally and ventrally, the strongest being ventral. The 
dactylus, long and slender, has a small if stout accessory claw, and between it and the 
terminal claw is a long seta. 
The first pair of pleopoda form an operculum over the remainder in the female. 
The sympodite of the male is a narrow structure; the outer margin is curved gently 
outwards for about two-thirds of its length, it then tapers to a point. Against the 
exterior curvature is seen the ovate exopodite of the succeeding pair. 
VOL. V. 
P 
