Isehyrocerus 661 



Pleon Segment 3, postero-lateral corners acute. Eyes wanting. Antennae 

 1 and 2 nearly as long as body, with long setae. Antenna 1, 1^* Joint 

 longer than head, 2*^ luuch longer than 1^*, 3'^ nearly as long as 2^; 

 flagelhira with 5 elongate joints; accessory flagellum 1-jointed, half as long as 

 1^* Joint of primary. Antenna 2, ultimate Joint of peduncle long, slightly 

 shorter than peuultimate; flagellum as in antenna 1. Gnathopods 1 and 2 

 rather feeble, 6*'* Joint oval, without spines, merely furnished with delicate 

 bristles; 2"^ gnathopod not much larger than 1^*. Peraeopods 3 — 5 almost 

 equal in length; 2<^ Joint oblong oval. Uropods 1 — 3 slender. Colour uniform 

 white. L. 3 mm. 



Arctic Ocean (aorth-west of Finmark). Cold area; depth 2090 m. 



8. I. brevioornis (O. Sars) 1879 Podocerus h., Q. O. Sars in : Arch. Naturv. 

 Kristian., vA p. 4(50 | 1882 P. b., Hoek in: Niederl. Arch. ZooL, suppl. 1 nr. 7 p. 63 | 

 1885 P. h., G. 0. Sars in: Norske Nordhavs-Exp., v. 6 Crust. I p. 207 t. 17 f. 2a -c | 1893 

 Podoceropsis sophiae (part.), A. üellaValle in: F. Fl. Neapel, u 20 p. 452. 



Body rather stout. Head, lateral lobes acute. Side-plates pretty well 

 developed, 5*^ notably less deep than 4*^. Pleon segment 3, postero-lateral 

 coruers quadrate. Eyes wanting. Antennae 1 and 2 short, robust, not half 

 as long as body, with short setae. Antenna 1, 1** Joint shorter than head, 

 3^ longer than l^S shorter than 2*^; flagellum 7- or 8-jointed; accessory 

 flagellum 1-jointed, nearly as long as 1^* Joint of primary. Antenna 2, 

 flagellum shorter than ultimate Joint of peduncle, 6- or 7-jointed. Gnatho- 

 pods 1 and 2 robust, similar, but 2'\ especially in d, considerably larger; 

 6*^ Joint broad, compressed, the oblique palm well defined from the bind 

 margin, with powerful palmar spines in gnathopod 1, and a distinct angular 

 projection in gnathopod 2. , Peraeopods 3 — 5, 2^ Joint rather broad, especially 

 in peraeopod 5. Uropods 1 — 3 not very elongate, in particular uropod 3. 

 Colour whitish. L. 6 — 9 mm. 



North-Atlantic and Arctic Ocean (Storeggen Bank and in open sea; lat. 63** N., 

 long. 5**E. ; round Bear Island and Spitzbergen, depth 275 — 1444 m; lat. 74*' N., long. 

 45» E., depth 301 m). 



9. I. tuberculatus (Hoek) 1882 Podocerus t., Hoek in: Niederl. Arch. Zool., 

 suppl. 1 nr. 7 p. 64 t. 3 f. 32 | 1893 P. t., A. DellaValle in: F. Fl. Neapel, v.2Q p. 443 

 t. 57 f. 17 I 1894 P. t, T. Stebbing in: Bijdr. Dierk., v. 17 p. 44 ; 1888 P. hoeki, T. Stebbing 

 in: Kep. Voy. Challenger, «.29 p. 1136 t. 120. 



Head, lateral lobes obtuse with minute point iu front. Side-plate 4 

 the largest. Pleon segment 3, postero-lateral corners obtusely quadrate. 

 Eyes wanting. Antenna 1, 3*^ Joint a little longer than 1**, decidedly 

 shorter than 2*i; flagellum 6-jointed, longer than 3*^ Joint of peduncle; 

 accessory flagellum half or less than half as long as 1*^ Joint of primary, 

 1-jointed. Antenna 2 longer, ultimate joiut of peduncle slightly longer 

 than penultimate or than the ö-jointed flagellum. Gnathopod 1, 5^^^ Joint cup- 

 shaped, 6*^*^ broad, proximally oblong, but narrowing distally ; the palm longer 

 than bind margin, very oblique, straight, finely serrate, defined by palmar 

 spines, among which the curved serrate finger closes. Gnathopod 2 in Q like 

 gnathopod 1, but with the ^^^ joiut larger, and in the 6 of the same general 

 character, but with b^^ Joint comparatively smaller, 6*^ large, more oblong, with 

 the palm obliquely sinuous, irregularly tuberculate, defined by a small tooth, 

 within which the broad, somewhat denticulate finger closes. Peraeopods 1 

 and 2 rather stout. Peraeopods 3 — 5, 2*^ Joint oblong, in peraeopod 4 narrowing 

 distally. Uropod 3 rather short, peduncle about 2^2 times as long as rami, 



