18 G. O. Sårs. 



The caudal rami (see fig. 4) are conspicuously asym- 

 metrical, the right ramus beiog broader and more exstant 

 than the left, and the 3 outer marginal setæ on this ramus 

 are peculiarly transformed, having lost their cilia and assumed 

 the character of soft, band-like spines lying in close approxi- 

 mation. 



The anterior antennae are very unequal in appearance. 

 While the left antenna has preserved its original stucture 

 unaltered, the right one (see ûg. 4 and 14) is pecuKarly modi- 

 fied to form a prehensile organ, whereby the number of 

 articulations has been somewhat reduced. It exhibits 3 

 successive sections, very sharply defined from each other, and 

 of nearly equal length. The 1st section is the least 

 modified, though the outer joints appear somewhat abnormal 

 from the very oblique sutures between them, and from some 

 spiniform projections not found in the female. The largest 

 of these projections is found on the 11th articulation (see 

 fig. 14). The middle section is considerably tumefied, and 

 oblong fusiform in shape, containing a strong, band-like muscle 

 which passes throughout its whole lengthy and joins the 

 terminal section. It is composed of 6 articulations, the 1st 

 of which is the smallest, and projects anteriorly to a straight 

 spiniform process. Each of the last 2 articulations, has 

 moreover anteriorly a peculiar appressed lamellar projection 

 finely striated transversally. The last section is connected 

 to the middle one by a very movable articulation, which 

 admits of its being doubled upon the former by the action 

 of the band-like muscle traversing this part It is only 

 composed of 4 distinctly-defined articulations; but it is very 

 probable that a fusion of originally distinct joints has taken 

 place. The 1st of the joints is the largest, and is somewhat 

 bent at the base, exhibiting anteriorly 2 successive appressed 



