REPORT ON THE AMPHIPODA. 1579 



Mandibles small, the distal end triangular, the lower edge of the triangle being the 

 striated cutting edge ; the secondary plate of the left mandible is nearly as large as the 

 principal, and similar except that it has not a projecting tooth at the top ; on the right 

 mandible there is a small process shaped like a broad broken spine. 



Maxillipeds. — The inner plate and the joint to which it is attached carinate down the 

 centre on the inner side, its distal margin arched ; the outer plates curving over the inner 

 one, with sinuous inner margins, at first convex, then concave, fringed with seven small 

 tubercles, in each of which a short setule is planted. 



First Gnathopods. — Side-plates much deeper than broad, produced below to a sharp 

 point, the lower part of the concave front margin and all the lower margin serrate, the 

 hinder margin rounded below. The first joint attached a little above the middle of 

 the side-plate and not reaching much below it, the hind margin convex, the front still 

 more bowed, except at its two extremities ; the second joint very short, broader than long, 

 with a spinule near the hinder apex ; the third joint very bttle longer, somewhat broader 

 than the second, with a spinule similarly placed but longer ; the wrist broader than the 

 first joint and behind about as long ; the front margin convex, with a spinule near the 

 apex, the wrist here attaining its greatest breadth ; the hind margin much longer than 

 the front, convex at the base, thence running in almost a straight line to form a long 

 apical tooth, the inner margin of the process being cut into two or three smaller teeth, 

 the outer surface carrying a few spines and the inner surface crossed by a large group ; 

 the hind margin is bordered with eight spinules, and along the distal half serrate, and 

 minutely pectinate between the serrations ; the very convex front margin of the small 

 hand is not continuous with that of the wrist, but set considerably back, whde the 

 straight, finely but irregularly denticulate, hind margin overlaps without reaching be) r ond 

 the inner margin of the process of the wrist ; numerous spines planted on the surface 

 of the hand within its hind margin antagonize with those on the inner surface of the 

 wrist ; the finger is very small, set on the front of the apex of the hand, curving over the 

 short remaining part of the faintly produced apical margin and across the sharp apical 

 tooth of the wrist ; there are small spines on the front margin and distributed on both 

 surfaces of the distal part of the hand. 



Second Gnathopods. — Side-plates with the front margin almost straight and smooth, 

 directed obliquely forwards, deeper than the hind margin ; the lower margin serrate, 

 slightly sinuous. Branchial vesicles oval, a little longer and much broader than the first 

 joint, speckled over with little hairs. The limb not unlike that of the first gnathopods, 

 but much larger ; the first joint a little sinuous, not quite so long as the wrist ; the 

 second and third as in the preceding pair, but larger ; the wrist very broad, and more 

 than twice as long as it is broad, the proximal part muscular ; the hind margin convex, 

 fringed with spinules, the distal two-fifths forming a triangular thumb, the apex of which 

 reaches beyond the hand, the inner or front margin of the process being slightly concave, 



