Stegocephalus, Stegocephaloides 91 



Synopsis of species : 

 Pleon Segment 3, lower margin serrate, hinder smooth . ... 1. S. inflatus . . p. 91 

 Pleou Segment 3, lower margin smooth, hinder serrate .... 2. S. siroilis . . p. 91 



1. S. inflatus Kreyer 1842 S.i., Kreyer in: Naturh. Tidsskr., vA p. 150 ' 1845 

 S.i., Kreyer in: Naturh. Tidsskr., ser.2 v.l p.522 t.7 f.3 : 1887 S.i., H.J.Hansen in: 

 DijmphnaUdb.. p.218 t.21 f. 10— 10c | 1888 S.i., T. Stebbing in: ßep. Voy. Challenger, 

 f. 29 p. 728, 1721 t. 137 a i 1891 S. i., G. O. Sars, Crust. Norway, v. 1 ]). 198 t. 69 1 1893 

 ä. i., A. DellaValle in: F. Fl. Neapel, t;. 20 p. 627 t. 59 f. 32—34 | 1855 S. ampulla (err., 

 non Cancer a. Phipps 1774!), T. Eell in: Belcher, Last arct. Voy., ».2 p. 406 t. 35 f . 1 | 

 1866 S. a. (part.), Goes in: Öfv. Ak. Förh., v. 22 p. 521 t. 38 f. 8 (not f. 9). 



Head with deflexed rostrum reaching eud of 1^* Joint of antenna 1, lateral 

 €orners rounded, somewhat projecting. Peraeon segiuent 1 not so long as 

 2^ and ^^ combined. Side-plate 4 twice as deep as segment, as broad as 

 side-plates 1 — 3 combined. Pleon segment 3, lower margin seiTate, hinder 

 smooth, angles acute. Antenna 1, A^^ Joint nearly twice as long as 2*^ and 3** 

 combined, with slight setulose expausion ; flagellum with 12 joints, 1®* not elongate, 

 shorter than accessory flagellum. Antenna 2 rather longer than antenna 1, 

 ultimate Joint of peduncle longer than penultimate, flagellum slender, subequal 

 to peduncle. Onathopod 1, 6^'^ Joint as long as the slightly dilated ö^'i. 

 Gnathopod 2, 6*^ Joint sublinear, longer than 5^'^. Peraeopod 4, 2"^ Joint 

 oblong quadrangular, lower bind corner quadrate. Peraeopod o, 2*^ Joint 

 much expanded, bind margin very convex, serrulate, lower corner acute. 

 Üropod 3, rami nearly twice as long as peduncle. Telson nearly twice as long as 

 broad, ending acutely, cleft beyond centre. Colour yeilowish with brown patches, 

 legs and antennae bauded. L., fuUy extended, 47 mm in rare iustances. 



Arctic Ocean; North- Atlantic (West-Norvvay, Shetland Isles, Nova Scotia). 

 Depth 188—376 m. 



2. S. similis ü. Sars 1891 S.S., G. 0. Sars. Crust. Norway, v.l p.200 t. 70 f . 1 ; 

 1893 S. s., A. DellaValle in: F. Fl. Neapel, u 20 p. 627 t. 50 f. 35. 



Head with very short obtuse rostrum, lateral corners rounded, very 

 slightly projecting. Peraeon segment 1 longer than 2*^^ and 3^ combined. 

 Side-plate 4 not nearly twice as deep as segment. nor as broad as side-plates 1 — 3 

 combined. Pleon segment 3, lower margiu smooth, hinder serrate, angle 

 not produced. Antenna 1 as in S. inflatus, but flagellum with 9 joints, 1^* longer 

 than accessory flagellum. Antenna 2 scarcely longer than antenna 1, ultimate 

 and penultimate joints of peduncle subequal, flagellum shorter than peduncle. 

 Gnathopod 1, 5*^ Joint much dilated, shorter than 6*^^ Peraeopods 4 and 5, 

 2^ Joint oval, longer in 5^^'^ pair than in 4*^>. Uropod 3 as in S. inflatus. 

 Telson not nearly twice as long as broad, ending subacutely, cleft beyond 

 centre. Straw-coloured, mottled with brown and reddish spots. L. 9 12 mm. 



Arctic Ocean and North-Atlantic (West- 

 Norway). Often but not always with S. inflatus. 



3. Gen. Stegocephaloides 0. Sars 



1891 Stegocephaloides, G. O. Sars, Crust. 

 Norway, v.l p. 201 | 1893 S. (part.), A. Della 

 Valle in: F. Fl. Neapel, i;. 20 p. 629. 



Like Stegocephalus (p. 90) in raouth- 

 organs and general appearance (Fig. 18), 

 but side-plate 4 with lower and hinder „. „ . . 



^ .. . 1 ,.tu 11 Flg. 18. S. christianiensis, 9 . 



margms meetmg m an angle; b"' smaller Lateral view. [After g. o. Sars.j 



