SYSTEMATIC REPORT 151 



telson, it very closely resembles M. macrops, but differs in the rather longer rostral plate, the slightly 

 longer antennal peduncle, the absence of spines on the distal third of the inner margin of the endopod 

 of the uropod and, especially, in the smaller eyes. These are set rather close together and are turned 

 outward so that, though the cornea really occupies only the distal part of the organ, as it does in 

 M. microps, it appears to extend laterally as in M. macrops. The eyes are larger than in M. microps and 

 the cornea is wider than the eyestalk, but the eyes do not extend laterally as far as the margins of the 

 carapace, and in dorsal view they do not cover the antennal scale (Fig. 34 A). 



M. intermedia may be distinguished from M. microps at once by the shorter eyestalks, the larger 

 cornea, the armature of the endopods of the uropods, the larger, more regular spines arming the 

 lateral margins of the telson and, particularly, by the deep, narrow cleft of the telson (Fig. 34A, L). 



The ' palp ' of the maxilla is expanded and is almost as long as broad, and the labrum is more pointed 

 anteriorly than in either of the other two species (Fig. 34 D, G). 



Distribution. This species has been taken at four stations off the Falkland Islands and at one in the 



Strait of Magellan. 



Mysidetes patagonica sp.n. 



(Fig. 35A-E) 

 Occurrence: 



St. WS 210. 29. v. 28 (day). North of Falkland Is., 161 m., 1 adult <J, 20 mm. 



St. WS 214. 31. v. 28 (day). North of Falkland Is., 208-219 m., 1 $, 16 mm., 2 juv. S3, 2 juv. ?$. 



St. WS 215. 31. v. 28 (dusk to night). North of Falkland Is., 219-146 m., fragments. 



St. WS 233. 5. vii. 28 (day). North of Falkland Is., 185-175 m., 1 adult 3, 19 mm. 



St. WS 234. 5. vii. 28 (night). North of Falkland Is., 195-207 m., 1 adult $, 16-4 mm. 



St. WS 236. 6. vii. 28 (dusk to night). North-east of Falkland Is., 272-300 m., 1 adult ?, 21 mm. 



St. WS 239. 15. vii. 28 (night). North-west of Falkland Is., 196-193 m., 4 S3, 8 $?, largest 17 mm., 12 juv. (1 $ 



of 16 mm. ovigerous). 



St. WS 244. 18. vii. 28 (day). West of Falkland Is., 253-247 m., 14 33, 25 ??, largest of both sexes 20 mm., 



fragments. Types. 



St. WS 583. 2. v. 31 (day). Magellan Strait, 14-78 m., 1 ovig. ?, 17 mm. 



St. WS 748. 16. ix. 31 (night). Magellan Strait, 30o(-o) m., 1 adult S, 16 mm. 



St. WS 758. 12. x. 31 (night). North of Falkland Is., ii2(-o) m., 2 S3, larger 17 mm. 



Description. Carapace very short anteriorly ; rostral plate acutely pointed with its apex reaching 

 the anterior margin of the eye-bases (Fig. 35 A). Antennular peduncles relatively short and slender; 

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

 Antennal scale slender, more than six times as long as broad, somewhat bowed, with outer margin con- 

 cave and inner margin convex; extending for about one-third of its length beyond the antennular 

 peduncle; peduncle short, less than two-thirds as long as the scale (Fig. 35 A, B). Thoracic appendages 

 with large, well-developed exopods; endopods of third to eighth pairs relatively short and slender with 

 the carpo-propodus composed of 9-10 sub-segments. Genital appendage of the male thick and much 

 shorter than is usual in the genus (Fig. 35 C). Uropods long and slender, exopod twice as long as the 

 telson and bowed outward; endopod armed along inner margin with a close regular row of about 

 30-32 very strong spines, extending from the statocyst to within one-fourth of the length from the 

 apex (Fig. 35 D). Telson short and broad, somewhat shorter than the sixth abdominal somite and less 

 than twice as long as broad at the base; cleft to nearly one-third of its length; proximal fourth of 

 lateral margins naked, the remaining three-fourths armed with a close row of 30-33 strong spines, 

 which increase in size towards the apex and are not arranged in series of larger spines with smaller 

 ones in the spaces between them ; apical lobes broad and bluntly rounded, armed with five large spines, 

 of which the outermost two form the natural culmination of the row of strong lateral spines and the 



