300 



with imperfectly-developed visual elements, otherwise of the usual appearance, 

 pigment light red. Superior antennas in female nearly attaining the length of 

 the cephalon and the 4 anterior segments of mesosome combined, and reaching 

 somewhat beyond the peduncle of the inferior ones, 2nd joint of the peduncle 

 very elongated and slender, considerably exceeding in length the 1st one, 

 flagellum shorter than the peduncle, and composed of about 9 articulations. 

 Inferior antennae about l /s longer, the 2 outer joints of the peduncle nearly 

 of equal length, flagellum but little shorter than the peduncle. Anterior 

 gnathopoda comparatively rather short and stout, propodos oval in form, 

 about twice as long as it is broad, and somewhat curved, palm distinctly 

 denned below, and about the length of the hind margin, carpal lobe narrow 

 linguiform and produced beyond the latter. Posterior gnathopoda more slender, 

 propodos narrow and elongated, more than 3 times as long as it is broad, car- 

 pal process extremely slender, extending far beyond the hind margin of the 

 propodos. The 2 anterior pairs of pereiopoda rather strong, carpal joint com- 

 paratively large, about the length of the meral joint, broadest at the base and 

 gradually tapering distally, with the inferior edge arcuate and densely setous, 

 propodal joint nearly of same length but much narrower, dactylus scarcely 

 more than half the length of the latter joint, and rather slender. The 

 2 succeeding pairs of the usual structure, with the dactylus rather short 

 and somewhat compressed. Last pair of the usual slender form, basal joint 

 rather broad, rounded oval, with the posterior edge arcuate, carpal joint about 

 the length of the propodal one, and but little longer than the meral joint. 

 Telson comparatively small, quadrangular, tip transversely truncated. Body 

 whitish, pellucid, without any trace of pigmentary ornamentation. Length of 

 adult female 8 mm. 



Remarks. As to the structure of the gnathopoda, this new species 

 agrees somewhat with M. carinatus, but is easely distinguishable by the very 

 narrow and acuminate rostrum, the small size of the eyes, the comparatively 

 much more elongated superior antennas, and finally, by the absolute want of 

 any pigmentary ornamentation. 



Occurrence. I have met with this form in a few places off the west 

 coast of Norway, and recently also in the Trondhjemsfjord and at Apelvser, 

 Namdal. It is a true deep-water form, occurring only in depths ranging 

 from 60 to 200 fathoms. 



