274 "TERRA NOVA" EXPEDITION. 



the Falklands, soiitliern extremity of S. America, extreme south of New Zealand and 

 the outlying sub-antarctic islands, an area bounded to the north and south by the 

 isotherms of 12° C. and 6° C. respectively — with two districts, Magellan and Antipodes. 

 The following list includes all the species of Mysidacea of which I can find records 

 from the two zones as defined by Regan, and the species have been tabulated under the 

 same districts as used by him for fishes. As far as the evidence available from this 

 list goes, it supports Regan's conclusion that the x\ntarctic zone should include both 

 the South Georgia area and Kerguelen. It should be emphasised, however, that 

 the Mysidaceans included in the table do not present any evidence of a distinct and 

 definite Antarctic Mysidacean fauna. They represent part of a deep and cold water 

 fauna which is more or less distributed over the deeper oceans of the world. Onl)^ 

 one genus, Antarctomysis, is peculiar to southern polar waters. All the other genera 

 have representatives in the deep water of the North Atlantic, Mediterranean and 

 Pacific Oceans, and are therefore inconclusive for separating an Antarctic from a general 

 deep water element. It should, however, be borne in mind that the records of Mysidacea 

 from the Antarctic zone, as defined by Regan, are all from deep water. Nothing is 

 yet known of the littoral Mysids of the various lands and islands in that zone, and it 

 is from such a littoral fauna, if it exists, that evidence will be obtained from which 

 deductions of a zoo-geographical kind can be made. Similarly, ignorance of the 

 Mysidacean fauna of the sub-antarctic zone, as defined by Regan, makes it impossible 

 to institute a comparison between that zone and the Antarctic. The only record 

 from the Antipodes district is of a species allied to the littoral faima of temperate 

 New Zealand. From the Magellan region, Mysidopsis acuta and Neomysis patac/ona 

 are representatives of temperate genera, Mysidetes crassa, of a deep water genus of 

 wide distribution, and Antarctomysis sp., of a genus whose known distribution is 

 otherwise purely Antarctic. 



Accepting Regan's definition of the Antarctic zone, twenty-one species of Mysidacea 

 are at present known from that region. It should be noted that Echinomysis chuni, 

 stated by Illig (1905) in his preliminary paper to have been obtained in the Antarctic 

 Ocean, is probably not Antarctic at all, as in his later paper dealing with this species 

 Illig (1912) gives no Antarctic localities at which it was taken. 



As with the Isopoda collected by the " Terra Nova," the Mysidacea are interesting 

 from the light which they throw on the Mysidacean fauna of New Zealand, a region 

 hitherto practically unexplored from this point of view. The first Mysid to be recorded 

 from New Zealand was Siriella denticulata, described by G. M. Thomson in 1880 under 

 the genus Mysis, and subsequently in 1900 referred to its correct genus. In 1881 

 Kirk described a New Zealand species imder the name Mysis meinertzhagenii, but it 

 is impossible to recognise even the genus from the short and inadequate description, 

 and efforts to trace the type specimen have failed. This species must remain, therefore, 

 for the present, problematical. 'In 1900 G. M. Thomson described a species common in 

 brackish waters near Dunedin under the name Tenagomysis novae-zealandiae, and this 



