429 



always found to be smaller and more obtuse. Without a closer examination, 

 however, both species may easily be confounded, and I find it indeed most 

 probable, that the statements of other authors about the occurrence of 7i. 

 Helleri in the Arctic Seas, may more properly be interpreted as applying to 

 the species here treated of. 



Occurrence. The species would seem to occur along the whole 

 coast of Norway, from the Christianiafjord to Vads0, and is generally met 

 with in very considerable depths, ranging from 100 to 400 fathoms, muddy 

 bottom. 



Distribution. - - Skagerak (Stockholm Museum), the Barents Sea (Hoek, 

 as T. Helleri), the Kara Sea (Stuxberg, do.), Spitsbergen (Norw. North. 

 Atl. Exped.). 



9. Rhachotropis leucophthalma, GK 0. Sars, n. sp. 



(PI. 151, fig. 2). 



Body somewhat less slender than in the last 2 species, otherwise of 

 a very similar appearance. None of the segments of mesosome produced 

 dorsally; those of metasome distinctly tricarinate, with well-defined dorsal 

 and subdorsal projections; the projection of 1st segment of urosome unusually 

 large and triangularly pointed. Cephalon scarcely attaining the length of 

 the first 2 segments of mesosome combined, lateral corners very narrow, 

 linguiform. Coxal plates nearly as in the last 2 species. Last pair of 

 epimeral plates of metasome broadly rounded at the lateral corners, posterior 

 edge considerably curved and, as usual, strongly serrated. Eyes quite 

 rudimentary, and replaced by 2 somewhat irregular patches of a yellowish 

 white pigment, without any trace of visual elements. Superior antennae not 

 nearly attaining half the length of the body, the first 2 joints of the 

 peduncle about of same length, last joint much smaller, flagellum about the 

 length of the peduncle. Inferior antennae a little longer than the superior, 

 and of the usual structure. Gnathopoda comparatively strongly built, and 

 of much the same appearance as in the 2 preceding species. Pereiopoda 

 rather slender and elongated, though not nearly to such an extent as in 

 Pi. macropus, the last pair being far from attaining the length of the whole 

 body. Uropoda nearly as in the latter species. Telson, on the other hand, 

 not nearly so much elongated, and having the outer part more distinctly 

 attenuated, cleft extending about to the middle. Body light yellowish, partly 

 tinged with a diffuse, reddish orange pigment, assuming, on the buccal area 

 and the gnathopoda, a pinkish hue. Length of adult female reaching 14 mm. 



55 - Crustacea. 



