74 DISCOVERY REPORTS 



Boreomysis plebeja Hansen, 1910 

 (Fig. 1 1 A) 



1910 Boreomysis plebeja Hansen, p. 24, pi. II, figs. 2.a-zd. 

 1930 Boreomysis plebeja, Illig, p. 414. 



Occurrence : 



St. 1604. 29. x. 35 (night). West of Walvis Bay, 620-500 m., 1 nearly adult o", 12-4 mm. 

 St. 1606. 31. x. 35 (night). West of Orange River estuary, 600-500 m., 1 imm. S, 1 imm. $, 14 mm. 

 St. 1989. 10. iii. 37 (day). Off S. Georgia, 1500-120001., 1 juv. $, 8-8 mm. (Colour note 'rich red head anteriorly, 

 shading off posteriorly to very pale pink; eyes brilliant orange'.) 



Remarks. This species was founded by Hansen on a single immature female with the marsupium 

 not yet developed. The Discovery collection contains one adult male (unfortunately with the pleopods 

 badly damaged), one immature male and an immature female with small but well-developed marsu- 

 pium. These specimens are considerably larger than the type and the slight differences in proportions 

 which they show are probably due to growth changes. 



The species can be recognized by the long acute rostrum, the small eyes with very long ocular 

 papillae (which in these specimens extend considerably beyond the anterior margin of the cornea), 

 the long slender uropods and the comparatively broad telson with no trace of a dilatation at the base 

 of the cleft. In these specimens the antennal scale is broader than in the type, being only three times 

 as long as broad at its widest part. The apex, however, agrees with the type, being relatively long and 

 extending clearly beyond the tooth which terminates the unarmed outer margin of the scale. 



Hansen did not figure the uropods, but recorded that the exopods were long and slender and that 

 the proximal fourth of the outer margin was naked and terminated by a single spine. The Discovery 

 specimens agree with this description and I can now add the fact that the endopods, which are also 

 very slender, are armed on the inner margins, just distal to the statocyst, with two long delicate 

 spines (Fig. 1 1 A). 



Distribution. The type was taken off the west of the Moluccas. Illig (1930, p. 414) recorded 

 a single small immature female from the Benguela Current to the north-west of Cape Town. The 

 Discovery specimens were also taken in the Benguela Current, somewhat farther north — from west 

 of the Orange River estuary and from west of Walvis Bay. 



Boreomysis sibogae Hansen, 1910 



1910 Boreomysis sibogae Hansen, p. 25, pi. ii, figs. 2 a ~ c - 

 1 95 1 Boreomysis sibogae, Tattersall, p. 51. 



Occurrence : 



St. 85. 23. vi. 26 (night). West of Cape Town, 200o(-o) m., 1 imm. $, 18 mm. 



St. 693. 10. v. 31 (day). Mid-Atlantic, equatorial zone, 250-0 m., 1 imm. $, 20 mm. 



St. WS 26. 18. xii. 26 (night). North of Bird I., South Georgia, 1000-750 m., 1 imm. ?, 7 mm. 



St. WS 29. 19. xii. 26 (day). North-west of South Georgia, 50-0 m., 1 imm. ?, 22 mm. 



Distribution. This species has been recorded from the Dutch East Indies (Hansen, 1910), 

 Indian Ocean off Ras Hafun (Illig, 1930) and the Sea of Okhotsk (Tattersall, 1951). I somewhat 

 doubtfully refer the specimens from stations 85 and WS 29 to B. sibogae. They are damaged, but they 

 appear to resemble this species more closely than any other. If my identification of them is correct, 

 the known geographical range of the species is considerably extended to the southward. 



