64 THE VOYAGE OF H.M.S. CHALLENGER, 



promiuent and obtusely rouinled. The antero-lateral corners are also less prominent, 

 though distinctly projecting, and the inferior edges are ii'regularly llexuous, and through- 

 out smooth. The surface of the carapace in both sexes is quite even, without any trace 

 of crests or spines, except a few small denticles on the posterior gibbous part, more 

 distinct in the female. 



The eyes, as in the two other known species of the genus, are widely separated, and 

 located on each side of the frontal lobe at the base of the pseudorostral projection. 

 Each of them exhibits a distinct ocular pigment and three strongly projecting corneal 

 facets, much larger in the male than in the female. 



The exposed part of the trunk is scarcely more than half as long as the carapace, 

 and composed of five well-defined segments, the first of which, however, is very narrow. 

 The epimeral plates are evenly rounded and quite smooth. 



The tail is very slender in both sexes, with the penultimate segment the longest. 

 The last segment is j^roduced in the middle posteriorly to an obtuse angle. In the 

 female a few very small denticles occur on the dorsal surface of each segment, whereas 

 in the male all the segments are quite smooth. 



As to the colour of the specimens freshly mounted m Canada balsam, the female 

 specimen is rather pellucid, with only a few dark brown patches, one of which occurs on 

 each side of the carapace close to the inferior edge, another across the penultimate 

 caudal segment (see fig. 4). In the male the whole carapace, as also most of the body, 

 is of a much darker brownisli hue. In both sexes a dark transverse band is observed 

 on the first pair of legs occupying the meral joint, and also on the second pair of 

 gnathopoda a similar band occurs. 



The antennulse are quite similar in the two sexes, and rather slender, with one of 

 the flagella very small and knob-shaped. 



The antennae of the adult male (see fig. 5) are much shorter than the body, and 

 scarcely reach beyond the third caudal segment. The distal part of the peduncle is 

 distinctly biarticulate and densely beset along the lower edge with rather slender sensory 

 bristles. The flagellum is very narrow and composed of much elongated joints. 



The first pair- of legs are about as long as the carapace, with the carpal and pro- 

 podal joints rather slender and subequal, and the terminal considerably shorter. 



The second pair of legs are much shorter than the first, with the terminal joint 

 linear and provided with a few stiff' bristles on both edges and at the tip, the latter 

 being the longest. 



The exopodites of these two pairs of legs, as also of the second pair of gnathopoda, 

 are remarkably small, especially in the female, with the basal part not at all dilated. 



The three posterior pairs of legs are in the female simple, without any trace of 

 exopodites, and very slender, considerably longer than the second pair, and about equal 

 in length. They are almost quite naked, and have the carpal and propodal joints very 



