485 



plates nearly as in the preceding species. Epimeral plates of metasome, 

 however, having the posterior edge perfectly smooth, those of last pair 

 produced at the lateral corners to a dentiform projection. Eyes about as in 

 M. spinosa. Superior antennae scarcely attaining the length of the body; 

 2nd joint of the peduncle nearly twice the length of the 1st; 3rd joint much 

 more elongated than in M. spinosa, equalling 2 /s of the length of the 2nd; 

 flagellum but little longer than the peduncle, and composed of about If) 

 articulations, accessory appendage nearly as long as the last peduncular joint 

 and 4-articulate. Inferior antennae but little shorter than the superior, last 

 joint of the peduncle exceeding in length the penultimate one, flagellum 

 scarcely as long as the former joint. Anterior gnathopoda nearly as in 

 M. spinosa, though with the carpal expansion somewhat smaller. Posterior 

 gnathopoda rather unlike those in the said species, and but little different 

 in their structure from the anterior ones, the carpus being expanded below 

 in a similar manner, and the propodos being subfusiform in outline, with the 

 dactylus rather elongated The 2 anterior pairs of pereiopoda having the 

 carpal joint about the length of the propodal one, and scarcely longer than 

 the meral joint. The 3 posterior pairs nearly as in M. spinosa, except that 

 the basal joint of the antipenultimate pair is not produced at the infero-posteal 

 corner. Last pair of uropoda excessively elongated, being nearly 3 times as 

 long as the urosome, otherwise of a structure similar to that in- the preceding 

 species. Telson somewhat less produced and having 2 pairs of auditory seta3 

 dorsally, and only a single lateral denticle on each side close to the base; 

 cleft extending beyond the middle, and somewhat wider than in M. spinosa, 

 terminal lobes unequally bidentate, with the apical spine much shorter than 

 in that species. Colour in the living state of the animal not yet stated. 

 Length of adult female 8 mm. 



Remarks. In its external appearance this new species is so very 

 much like the preceding one as easily to be confounded with it. On a closer 

 examination it is however readily distinguishable by the different armature 

 of the metasome, by the much fuller development of the last peduncular joint 

 of the superior antennas and of their accessory appendage, and finally, by the 

 extremely elongated and slender last pair of uropoda, which, however, as in 

 the other species, are very brittle, and therefore easily broken off. 



Occurrence. A few specimens of this form were long ago collected 

 by the author off the west coast of Norway (the exact locality not stated), 

 but were at that time confounded with M. spinosa. 



