428 

 8. Rhachotropis macropus, Gr. 0. Sars, n. sp. 



(PL 161, flg. 1). 



Very like B. Helleri, as to its general appearance, but having none 

 of the anterior segments of mesosome raised dorsally. Dorsal projections 

 comparatively small, that of last segment of metasome exactly of same 

 appearance as the 2 preceding ones, that of i;rosome of moderate size. 

 Cephalon and coxal plates nearly exactly as in the said species. Last pair 

 of epimeral plates of metasome narrowly rounded at the lateral corners, 

 posterior edge not much curved, but strongly serrated, the serrations being 

 continued for some distance also on the inferior edge. Eyes large, roiinded, 

 with distinct visual elements, pigment dark brown, with a whitish coating. 

 Superior antenna^ in female comparatively longer th&n m B. HeUeri , attaining 

 nearly half the length of the body, 2nd joint of the peduncle fully as 

 long as the 1st, last joint exceeding half the length of the former, both 

 densely edged with calceola? inside, flagellum scarcely attaining the length 

 of the peduncle. Inferior antennae nearly of same length as the superior, 

 last joint of the peduncle considerably longer than the penultimate one, 

 flagellum not nearly attaining the length of those joints combined. (Tuathopoda 

 much of same sti-ucture as in 11. Helleri. Pereiopoda, on the other liand, 

 much more elongated and slender, last pair of quite an unusual length, 

 exceeding even that of the whole body. Last pair of uropoda with the 

 rami broadly lanceolate in form, and having but a small number of minute, 

 marginal spinules, the inner ramus somewhat larger than the outer. Telson 

 very large, reaching considerably beyond the uropoda, and quite unarmed, 

 outer part but very slightly tapering distally, cleft extending to the middle 

 of the telson, terminal lobes somewhat unequal. Body whitish, ornamented 

 with irregular patches of a reddish orange pigment, the patches being gener- 

 ally smaller and less confluent than in B. Helleri: antennae, l)uccal area, 

 and legs partly tinged with the same pigment. Length of adult female 

 attaining 16 mm. 



Bemarls. — Li its general appearance this new species is so very 

 like B- Helleri, as easily to be confounded with it, especiallj^ as the brittle- 

 ness of the pereiopoda causes them in most of the specimens captured to be 

 more or less broken. In uninjured specimens the extraordinary length and 

 slenderness of the pereiopoda, and more especially of those of last pair, will 

 at once serve for distinguishing this form from any of the other species. 

 Moreover the last dorsal projection of the metasome is in this form exactly 

 of same appeai'ance as in the 2 preceding ones, whereas in B. Helleri it is 



