134 THE VOYAGE OF H.M.S. CHALLENGER. 



protected by a mass of hair on the under and outer side of the orbit, as well as by a fringe 

 of the same on the upper surface, that almost hides it from view, more especially in the 

 female. 



The first pair of antennae (fig 1 c, 6) has the first joint dorsally concave, the inner 

 margin projecting upwards so as to form, with the corresponding inner margin on the 

 opposite side, a crest, which is fringed with small teeth and long hairs, and produced 

 forwards to a point ; the second joint is small, narrow, and fringed with hairs on the inner 

 and outer sides ; the third is small, and similarly fringed with hairs, and carries at the 

 extremity two flagella; the outer is more slender, and built up of numerous small 

 bead-like articuli ; the inner has the articuli longer and broader. 



The second pair of antennae (c), including the coxa, articulates with the metope, it 

 carries a long projecting phymacerite, the extremity of which is flattened, turned 

 upwards, fringed with hairs, and covered by a membranous tissue, which impinges 

 against the lower surface of the coxa of the first pair of antennae, where a hollow 

 impression exists to receive it ; the second joint carries at its outer distal extremity 

 an obtusely-pointed scaphocerite fringed with long hairs, and on the inner a short, 

 strong tooth ; the next joint is narrower than the preceding, is thinner on the inner 

 than the outer side, and fringed with a row of very long hairs, and is anteriorly 

 produced to a short but strong tooth ; the terminal joint is cylindrical, narrower, and 

 shorter than the preceding, and is also fringed with long hairs ; the flagellum is long 

 and slender, and resembles the inner of the first pair. 



The mandibles are large and powerful, and are deeply serrate along the incisive 

 margin of the psalisiform blade, the centre of which is furnished with a strongly project- 

 ing pointed tooth, advanced considerably beyond the others, which gradually recede to 

 the upper and lower extremities, which are also armed with a strong and pointed tooth ; 

 the mandibles carry a Inarticulate synaphipod, which folds and lies within the hollow of 

 each mandible. 



The first pair of siagnopoda consists of a biramose uni-articulate appendage, flat, thin, 

 rigid, and curved longitudinally, the extremities armed with long spines and hairs, lying 

 closely against the metastoma or posterior lip, which consists on each side of a long and 

 slender styliform membranous process, closely impacted diagonally against the 

 mandibles. 



The second pair of siagnopoda consists of a large foliaceous plate extending both 

 anteriorly and posteriorly, and two small branches, one slender and pointed, the other 

 flat and spatuliform, and folded back upon the larger plate. The two smaller have the 

 edges smooth, but the largest is surrounded by a closely-set fringe of equally long hairs, 

 and has the surface flecked with fine cilia, sparsely distributed. 



The third pair of siagnopoda (fig. 32) is foliaceous and convolute ; the upper extremity 

 is constricted so as to form a chamber or pocket into which a triangular articulated joint 



