I4 8 DISCOVERY REPORTS 



St. WS 213. 30. v. 28 (day). North of Falkland Is., 249-239 m., 3 <Jc?, 4 ??. largest 13-2, all imm. 



St. WS 227. 12. vi. 28 (dawn). Off Falkland Is., 320-298 m., 5 <$$, largest 16-6 mm., 4 $?, imm., 13 mm.; 



8 juv. 

 St. WS 229. 1. vii. 28 (day). North-east of Falkland Is., 210-271 m., 2 adult SS, i5~ l6 mm - 6l J uv - 

 St. WS 233. 5. vii. 28 (day). North of Falkland Is., 185-175 m., 2 ??, 15 mm., adult, 1 juv. 

 St. WS 234. 5. vii. 28 (night). North of Falkland Is., 195-207 m., 4 S$, 8 $?, largest 14 mm., all imm. 

 St. WS 236. 6. vii. 28 (dusk to night). North of Falkland Is., 272-300 m. Two tubes: (i) 5 <?<?, 15-6-1 5-8 mm., 



1 ? (imm.), 14 mm., 1 small juv.; (ii) 10 $$, 17 $? (some ovigerous), 15-8-16 mm., fragments. 

 St. WS 244. 18. vii. 28 (day). West of Falkland Is., 253-247 m., 2 <$S, 2 ??, largest adult 15-6 mm. 

 St. WS 245. 18. vii. 28 (night). South-west of Falkland Is., 304-290 m., 11 $? and large number of fragments in 



bad condition. 

 St. WS 772. 30. x. 31 (day). North of Falkland Is., 309-163 m., 92, nearly all adult, largest 160 mm. Types. 

 St. WS 818. 17. i. 32 (day). West-south-west of Falkland Is., 272-278 m., 9 adult $$, largest 16 mm., 14 adult 



$$ (3 ovigerous), 15-16 mm., 5 juv. 

 St. WS 839. 5. ii. 31 (dusk to night). South-west of Falkland Is., 503-534 m., 81, largest 16 mm., many adult. 

 St. WS 871. 1. iv. 32 (day). South-west of Falkland Is., 336-342 m., 1 adult $, 16 mm., 1 imm. $, 14 mm., 1 adult 



$, 16-0 mm., fragments. 

 St. MS 68. 2. iii. 26 (day). Cumberland Bay, South Georgia, 220-247 m., 6 SS, 1 ?> largest 14 mm., 5 small juv., 



fragments. 



Description. Carapace very short anteriorly, leaving the whole of the eyes completely uncovered; 

 rostral plate with very short pointed apex (Fig. 33 A). Antennular peduncle moderately robust, with 

 the process from the outer distal corner of the first segment longer than the outer margin of the second 

 segment (Fig. 33 B). Antennal scale small, only slightly longer than the antennular peduncle; outer 

 margin nearly straight, inner margin convex ; peduncle small and slender, less than two-thirds as long 

 as the scale. The two spines on the outer distal angle of the sympod at the base of the scale are of 

 equal size and unusually long (Fig. 33 A, C). Eyes very large, extending laterally beyond the carapace, 

 with the cornea extending over nearly all the outer margins of the eyestalks (Fig. 33 A). Mandible 

 with the second segment of the 'palp' only very slightly expanded (Fig. 33 D). Thoracic endopods 

 slender with the carpo-propodus composed of 9-10 sub-segments. Genital appendage in the male 

 curving outward distally and extending to the mouth region (Fig. 33 E). Uropods with the endopods 

 short, only slightly longer than the telson ; armed along the inner margins with a close row of long, 

 slender spines from the region of the statocyst (where they are shorter) to within one-third of the 

 length to the apex; distal third of margins armed with 4-5 evenly spaced spines with the last one quite 

 near the apex (Fig. 33 F). Telson, lateral margins naked at the base; armed from the level of the stato- 

 cyst with a close row of spines which increase somewhat in size distally and may have one, rarely two, 

 very small spines in the spaces between the larger ones. These small spines may easily be overlooked 

 and in young individuals there are very few, especially at the distal end of the series; apical lobes 

 rounded, armed with one long spine, flanked on its inner side with two shorter equal spines; 

 cleft more than one-fourth of the telson in depth, armed on each side with about seventeen teeth 

 (Fig- 33 G). 



Length 16 mm. but females may be adult at less than 15 mm. 



Remarks. This species closely resembles M. posthon, which also has very large eyes, but may be 

 distinguished by the shorter antennal scale with its straight outer margin, the short uropods with the 

 very close row of spines arming the inner margin of the endopod and the distal spaced spines extending 

 nearly to the apex, by the relatively shorter telson' with its deep cleft and, particularly, by the armature 

 of its lateral margins. In M. posthon the intervals between the larger spines of the telson are much 

 longer, especially at the distal end of the series and are occupied with 5-9 small spines, but in 

 M. macrops the larger spines are closer together and there are never more than two small spines in a 



