REPORT ON THE AMPHIPODA. 1427 



First Maxilla}. — Inner plate seemingly wanting; the outer plate narrows distally, 

 carrying its three strongest spines on the apex, with six or seven slighter ones along 

 the inner margin, the series being continued by hair-like spines in pairs or singly at 

 four or five points ; the one-jointed palp reaches over the apex of the plate, its distal 

 margin carrying five little teeth, and the inner margin being also to some extent 

 denticulate. 



Second Maxilla}. — The inner plate is much shorter than the outer ; it has a small 

 spine at the apex with a spinule beside it on the outer side, and some cilia along the 

 inner margin ; the outer plate has a spine at the apex, one on the inner margin a little 

 below the apex, and cilia or setules along both margins. 



Maxillipeds. — The outer plates are very narrow, slightly curved in a lateral view, 

 closely adjoining one another from base to apex ; tapering, though not to a sharp point ; 

 the apex has a group of three spinules, and there are a few spinules at distant intervals 

 on the margins ; there are also some setules longer than the spinules ; the short inner 

 plate projects inwards a little beyond the base of the outer plates, and has a group of 

 spinules on its rounded apex, the inner margin in a lateral view being very concave. 



First Gnathopods. — Side-plates not distinct from the segment, the lower front 

 angle directed a little forward, more or less acute. The limb short, just half the length 

 of the second perseopods, less than a third of the third pergeopods ; the first joint almost 

 clear of the side-plate, rather longer than the remaining joints united, widening a little 

 distally, ornamented with stellate or dendritic markings; the second joint short, as 

 broad as long ; the third scarcely longer than the second, apically acute, lying almost 

 entirely upon the wrist, with some hair-like setules projecting upon the hind margin ; 

 the wrist cylindrical, widening distally, the hand also cylindrical, having its margins 

 continuous with those of the wrist, longer than the wrist, very much narrowed distally, 

 forming with its short slender finger a pencil-point ending. Gland-cells were not 

 observed in the first joint, but as the muscles of that joint are relegated, as in the 

 second gnathopods, to a narrow space in the hinder distal half, it may be assumed that 

 the large vacuum thus left is intended for gland-cells. 



Second Gnathopods. — Branchial vesicle nearly as long as and rather broader than 

 the first joint, with accessory inflations, one longitudinal starting from the base, the 

 others transverse. The limb very similar to that of the first gnathopods, but with all 

 the joints longer ; the first joint widest at the centre, with gland-cells along the whole 

 course ; the second joint twice as long as broad, and as long as the third joint ; the wrist 

 and hand longer, but more slender, than those of the preceding pair ; the finger more 

 elongate, with some extremely minute hairs visible on one edge. 



First Perasopods. — The side-plates small, produced at the lower part of the front 

 into a rounded lobe. The branchial vesicles of these and the three following pairs of 

 perseopods of very irregular and complex form, supplying a very large aerating surface. 



