REPORT ON THE AMPHIPODA. 973 



its base, and an accessory thread lying alongside of the stout apex ; the large curved 

 finger closes over the palm with its channelled inner margin, smooth except for a series 

 of small hairs ; the dorsal cilium near the base is quite small. 



Second Gnatkopods. — Side-plates oblong, rather narrower and but little deeper than 

 the preceding pair, the convex lower margin similarly notched. The branchial vesicles 

 longer than the first joint, very broad except at the base. The marsupial plates as long 

 as the branchial vesicles, but much narrower, fringed with many setae. The limb closely 

 agrees with that of the first gnathopods ; the first joint is longer, the third has fewer 

 spines on the hind margin, and a more acute apex, the hand is larger. 



First Perseopods. — The side-plates similar to the preceding pair, but rather larger. 

 The branchial vesicles rather broader than the preceding pair. The first joint reaching 

 beyond the side-plate, the front margin fringed with slender spines, the hind margin with 

 mixed groups of stiff spines and setaj or slender spines ; the second joint short, with 

 apical spines on the hind margin, and, as in the preceding limbs, some spiuules higher 

 up, the front lobe flattened ; the third joint much longer than the fourth and a little 

 longer than the fifth, with spinules on the front margin and spines at its somewhat 

 decurrent apex, and spines at six points of the front margin ; the spines of the next joint 

 are stronger, at five or six points of the hind margin, and at the apex of the front ; the 

 fifth joint has nine groups of spines along the hind margin, six spinules at four points of 

 the front margin, and a group at its apex ; the finger is short, about half the length of 

 the fifth joint ; the dorsal cilium very plumose, close to the base ; there is a smaller 

 cilium near the base of the nail. 



Second Perzeopods. — Side-plates broad, excavated behind for less than half the depth, 

 and less than a third of the width, the hind margin below the excavation sloping gently 

 forwards. The branchial vesicles very broad, longer than the first joint. The marsupial 

 plates as long as the first joint, but not quite so broad. The limb like that of the first 

 perreopods. 



Third Perzeoptods.— Side-plates as broad as the preceding pair or broader, the hind 

 lobe deeper than the front. The first joint of the limb broadly oval, subequally wide at 

 the basal and distal ends, the front margin fringed with spines, the hind margin serrate, but 

 not deeply; the second joint with flat hind margin and pointed apex, and having two groups 

 of spines on the front ; the third joint but bttle longer than the fourth, not longer than the 

 fifth, all three stout, with serrate front margins, the third joint with six, the fourth with 

 four, the fifth with seven groups of spines in front, each with an apical group behind, 

 and some smaller groups on the hind margin ; the finger small, curved, not half the 

 length of the fifth joint. 



Fourth Perseopods. — Side-plates with a deep hind lobe and a very small front one. 

 The branchial vesicles of great breadth, longer than broad, with a small accessory lobe 

 near the base. The limb similar in structure to that of the third perseopods, but con- 



