442 



Occurrence. I have myself only met with this form in a single 



place, viz., at Rost, the outmost of the Lofoten Isles, where a few specimens 

 were collected, during the Norwegian North Atlantic Expedition, from a depth 

 of 6 to 10 fathoms, sandy bottom. Boeck\s description was made from 

 a solitary specimen found off the Nordland coast. Out of Norway it has not 

 yet been recorded. 



5. Apherusa tridentata (Bruzel). 



(PL 156, fig. 1). 



Pammphiihoii tridentata, Bruzelius, Amphip. Gammar. K. Vet Akad. Handl. Ill, p. 74, fig. 13. 



Syn. : Halirages tridentatus, Boeck. 



Body comparatively less slender than in the 2 preceding species, and 

 somewhat compressed; last segment of mesosome and the 2 anterior ones of 

 metasome each produced dorsally to well-defined, acute projections. Cephalon 

 fully as long as the first 2 segments of mesosome combined, and rather deep, 

 rostral projection comparatively small, lateral corners obtusely rounded, 

 postantennal ones produced to a rather prominent spiniform projection. 

 Anterior pairs of coxal plates about as deep as the body; 1st pair not 

 expanded distally, but having the anterior corner somewhat angular and the 

 distal edge, like the 2 succeeding pairs, minutely serrated; 4th pair much 

 larger than the preceding ones and considerably widening distally, posterior 

 edge deeply sinuated, infero-posteal corner rather produced. Penultimate 

 pair of epimeral plates of metasome with the posterior edge coarsely serrated; 

 last pair forming a broad lamellar expansion, the lower corner of which is 

 acutely produced, whereas the upper one is boldly curved, posterior edge of 

 the expansion divided into 12 strong serrations, having between them small 

 bristles. Eyes in female of moderate size, in male considerably larger, in 

 both sexes oval reniform, with the anterior edge distinctly insinuated, pigment 

 very dark. Superior antennae in female scarcely exceeding l /s of the length 

 of the body, 1st joint of the peduncle about the length of the other 2 com- 

 bined, flagellum scarcely more than twice as long as the peduncle, and 

 composed of about 40 short articulations, the 1st of which is much the 

 largest. Inferior antennae nearly twice the length of the superior, and having 

 the fiagellum very slender, about 3 times as long as the peduncle. Gnathopoda 

 of the usual slender form and feeble structure, propodos about the length of 

 the carpus, and very slightly widening distally, palm, as usual, short, and 

 defined below by an obtuse angle. Pereiopoda moderately strong, basal joint 



