NO. 5.] ACCOUNT OF THE SPECIES. 135 



The frontal tentacle (see PI. XXXVI, fig. 6) has the capltulum more 

 tumefied, and very sharply marked off from the rod-like peduncle, which 

 appears to be divided into 2 segments. 



The antennulee (ibid.) are much more powerfully built than in the 

 female, and the joints are more sharply marked off from each other. The 

 musculation is also stronger, indicating a freer mobility of these limbs, 

 the muscles occupying the 2nd joint, and acting upon the terminal part, 

 being especially conspicuous. The slender seta issuing fi'om the upper edge 

 of this joint in the female is replaced by a short hook-like spine, curving 

 inwards. The apical appendages are present in the same number as in the 

 female; but they are all more or less transformed. The foremost seta is 

 very strong, and has the distal 3rd part abruptly bent downwards, the median 

 part being thickened, and armed below with recurved spinules. Of the 4 

 uniform sensory filaments present in the female, only 2 have retained their 

 sensory character, the hindmost exhibiting, however, a peculiar twisted form, 

 and extending straight behind. In the present species, these 2 sensory appen- 

 dages are of about equal size, whereas in other species their length is rather 

 different. The 2 remaining appendages have both assumed the character of 

 slender setae, much longer than the 2 above-mentioned sensory appendages, 

 though not nearly attaining the length of the foremost seta. On a closer 

 examination, only 3 of these appendages are seen to issue from the last 

 joint, whereas the other 2, one sensory and one setiform, are attached inside 

 the penultimate joint. 



The antennae resemble in structure those in the female, as regards the 

 basal part and the natatory ramus. On the other hand, the accessory ramus 

 is conspicuously transformed, and developed into a prehensile organ, termi- 

 nating in an anteriorly-curving claw, in addition to the apical appendages. 

 This claw is much larger on the right (fig. 7) than on the left antenna (fig. 8), 

 and a similar asymmetry is also found in the other species, probably having 

 some relation to the asymmetrical arrangement of the genital apparatus. 



Of the other limbs, only the penultimate pair, or the 2nd pair of legs 

 (fig. 9), differ somewhat from those in the female. They are, on the whole, 

 more powerfully developed, and each carry at the tip, 3 very long and densely 

 ciliated setae, which are all of exactly the same size, and lie close together, 



