6 E Canadian Arct.c Expedition, 1913-18 



Head; lateral lobes narrowly rounded. Eyes; pear-shaped, red. Antenna 

 1; 1st joint about twice as long as 2nd and 3rd combined, slightly produced at 

 the upper, inside, anterior edge, and provided on the upper, inside, posterior 

 end with a few plumose setae, flagellum in c?, 24 to 30 joints, in 9, 14 to 18 joints, 

 accessory flagellum, 5-7 joints, of which the first joint is about as long as all the 

 rest combined. Antenna 2 not much longer than 1, ultimate joint slightly 

 shorter than penultimate, flagellum in c?, 30 to 38 joints, in 9, 18 to 23 joints. 



Side-plate 1 expanded below, the lower anterior corner produced and 

 broadly rounded, the lower edge nearly straight, a slight notch bearing a minute 

 seta at lower posterior corner. Side-plates 2 and 3 with the sides nearly 

 parallel, slightly wider below, the lower edge nearly straight. Side-plate 4 

 deeply and broadly emarginate behind, the lower part wide, and the lower edge 

 nearly straight. 



Gnathopod 1, 6th joint about one-third longer than 5th with front edge 

 slightly convex and back edge slightly concave, palm oblique and provided 

 throughout its entire length with a single row of fine, sharp teeth and several 

 spines, dactyl curved, with a single small tooth or spine in the centre of the inside 

 edge, back of this tooth a row of very fine serrations, 4th and 5th joints provided 

 on their under surface with mats of fine setae. Gnathopod 2 as in 0. edwardsii 

 or 0. plautus, except that 5th and 6th joints are much more setose. 



The peraeopods are rather short and stout. Third abdominal segment 

 produced at the lower posterior corner into a small rounded lobe which varies 

 much in size. 



Telson a little longer than wide, sides convex, posterior border very slightly 

 emarginate and bearing two minute setae. 



The largest specimens measure about 19 mm. 



4. Onisimus brevicaudatus Hansen. 



1886. Onisimus brevicaudatus Hansen, Dijmphna-Togtets Ubd., p. 216, pi. 21, f. 7-7e. 

 1906. Onisimus brevicaudatus Stebbing, Tierreioh, Amph. I, p. 27, and synonymy. 



Station 29/; Lat. 70° 13' N., long. 140° 50' W., April 4, 1914, from stomach 

 of I Phoca hispida Schreber. Water depth about 30 fathoms. 6 specimens. 

 The specimens which Hansen described came from the Kara sea. 



5. Onisimus plautus (Kroyer). 



1845. Anonyx plautus Kroyer, Naturh. Tidsskr., ser. 2, vol. I, p. 629. 

 1906. Onisimvs plautus Stebbing, Tierreioh, Amph. I, p. 26, and synonymy. 

 1911. Onisimus plautus Staffers, Crust. Malacost., Campagne Arctique de 1907, du Due 

 d'Orleans, p. 16. 



Station 46c; Dolphin and Union strait. Northwest Territories (off Bernard 

 harbour), pelagic, over 38 feet water; February 19, 1916; 3 specimens. 



Distribution. — Arctic ocean, North Atlantic, and North sea, Skagerrak 

 (Bohuslan). 



6. Orchomenella groenlandica (Hansen). 



1887. Anonyx groenlandicus Hansen, Vid. Meddel., ser. 4, vol. 9, p. 72, pi. 2, f. 5-5g. 

 1906. Orchomenella groenlandica Stebbing, Tierreioh, Amph. I, p. 83, and synonymy. 

 1913. Orchomenella groenlandica Stephensen, Meddel. om Gii^nland, vol. XXII, p. 123. 



Station 41; Bernard harbour. Northwest Territories (outer harbour), July 

 20, 1915, 5 fathoms, sandy mud with algae; 1 specimen. 

 Distribution.- — Arctic ocean, East Greenland, Finland. 



