47o DISCOVERY REPORTS 



St.WS576. 17. iv. 31. Berkeley Sound, East Falkland Islands. 51 35' 00" S, 57 49' 45" W. Large 

 otter trawl, 34-24 m. 



M. subrugosa. 4 specimens, all $, 29-0-34-0 mm. 



M. gregaria. 20 specimens, 10 <J, 10 $, 28-0-37-0 mm. 

 S.S. 'Ernesto Tornquist.' Gulf of St George, Patagonia. 45°-47° S, 66°-68° W. All M. gregaria. 



23. iii. 29. Surface. 13 specimens, 4 <?, 9 $, 21-0-31-0 mm. 



27. iii. 29. Surface. 15 specimens, 5 <?, 9 $, 1 damaged, 18-0-29-0 mm. 



29. iii. 29. Surface. 20 specimens, 8 c?, 12 $, 20-0-28-0 mm. 



2. iv. 29. Surface. 18 specimens, 7 cj, 11 $, 20-0-32-0 mm. 



5. iv. 29. Surface. 21 specimens, 6 <?, 14 ?, 1 damaged, 20-0-33-0 mm. 



6. iv. 29. Surface. 14 specimens, 6 £, 8 $, 19-0-31-0 mm. 



The measurements of the specimens refer to the length of the carapace from its posterior border 

 to the tip of the rostrum. 



DISTRIBUTION 



Both Miinida subrugosa and M. gregaria are restricted to the southern hemisphere, 

 and their distribution, so far as our present knowledge goes, appears to be sharply 

 discontinuous. They have been found in abundance in the waters of New Zealand and 

 its sub- Antarctic islands, and in Bass Strait. In the South Atlantic they occur in plenty 

 at the Falkland Islands, Tierra del Fuego, the Magellan Straits and Patagonia. 

 M. gregaria has been recorded from the west coast of South America as far north as 

 latitude 41 30' S and on the east coast as far north as latitude 51 S. The corresponding 

 latitudes for M. subrugosa are 50 S on the west coast and 35 S on the east coast. 



The two species evidently inhabit comparatively warm water. They are found near 

 the Falklands and at Cape Horn, where surface temperatures vary between 5-5° and 

 9-0° C, but are entirely absent from the much colder waters of the South Shetlands, 

 South Georgia and Bouvet Island. At Tristan da Cunha and Gough Island, where 

 temperatures are higher than at the Falklands, neither species has been found, and there 

 are no records from the Kerguelen area. 



The vertical distribution of M. subrugosa extends from the shore to a recorded depth 

 of 600 fathoms (Henderson, 1888), and of M. gregaria from the shore to a recorded 

 depth of 60 fathoms (Young, 1925). 



SWARMING 



Both M. subrugosa and M. gregaria frequently occur in enormous shoals, the adults 

 usually on the bottom, while the Grimothea stage of M. gregaria has been on occasion 

 so plentiful at the surface as to colour the sea bright red over large areas. The adult 

 M. gregaria is also sometimes found in swarms at the surface. 



At St. 51 (4. v. 26, off Eddystone Rock, East Falkland Islands) the Grimothea stage 

 of M. gregaria was found to be swarming at the surface, and at the same time large 

 numbers of the adults of M. gregaria and adults and young of M. subrugosa were taken 

 in the trawl on the bottom at a depth of 105-115 m. So great was the catch of these 

 Crustacea that after preserving a long series of specimens the remainder was sent to the 

 cook and was much appreciated in the wardroom and on the mess-deck. At St. 223 



