ISOPODA. 



37 



these plumose setse, but here they vary in length, and on both lobes the plumose 

 structure exists only at the base, distally they become finely toothed. 



The maxilliped does not exhibit any special features. The basal joint is short 

 with the outer angles, particularly the anterior one, rounded. The masticatory lobe is 

 long, two-jointed, the inner margin straight throughout, but the outer margin of the 

 distal joint rounded. The distal margin is occupied by numerous short plumose spines. 

 The palp is five-jointed, the proportionate length of the various joints being about 

 3. 3'5. 6. 5. 2. The entire organ is richly clothed with long setse, more especially 

 internally and distally. With a one-inch objective these are seen to bear a number of 

 fine setae about the middle of their length. The epignath is carried on a small plate, 

 roughly ovate in shape, but having a flattened edge anteriorly. The epignath itself 

 is a large plate ovoid though flattened on one side ; it is just about as long as the 

 masticatory lobe. 



The whole of these mouth organs are richly pigmented with black arborescent 

 chromatophores. 



The first appendage of the mesosome is quite normal in general appearance, 

 provided with long setae on its ventral side from the distal extremity of the basis ; the 

 merus has both dorsal and ventral margins rounded, the former projecting forwards as 

 a blunt point with a small tuft of setse ; the distal extremity of the carpus projects in 

 a similar manner ventrally. The propodus is by far the largest joint, though not so 

 broad as the merus ; the dactylus, including the terminal claw, is about two-thirds the 

 length ; the claw has a very stout auxiliary. On the inner face of the propodus long 

 setse are arranged in eight or nine series ; these and a very large proportion of those 

 on or near the ventral margin are very finely toothed. 



The three following appendages are provided throughout their length from the 

 distal extremity of the basis with groups of very long and shorter simple setse. The 

 outer side of the basis carries a series of some half-dozen spines, and the ischium and 

 merus have a dorsal and distal spine. 



The three posterior pairs of appendages of the mesosome are strong, the 

 proportions of the joints of the middle one are 5 '5. 3 '25. 2. 1'8. 5. 4. The basis 

 bears several irregular but stout spinous processes along its dorsal border, the ventral 

 border of the remaining joints, except the dactylus, are fringed with spines, these only 

 develop as such along the ischium, dorsally there are a few scattered setse of variable 

 length. The dactylus has a few small setse dorsally, but is otherwise smooth. 



Five specimens of this species were taken in 300 fathoms off the Ice Barrier, 

 Bottom Mud, lat. 78. 25. 40. S., long. 185. 39. 06. E. Four of these are females, one 

 scarcely adult, two with ova, and one with numerous young not yet emerged from the 

 brood pouch. In these young the various segments are rendered conspicuous by 

 transverse ridges, but the only spinous armature visible on the entire body are the two 

 posterior horns of the urosome ; the cephalic horns are not present. 



