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 setae. The fiagellum 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 (h'g. 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 setae 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 setae. 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 exopoditc of the succeeding pair. 



VOL. V. P 



