Over a South Atlantic Continent 459 



that at present no equally or more primitive fish than 

 Pseudapliritis is known that is marine. 



An exactly parallel case Is furnished by Chimarrhich- 

 thys that is a freshwater genus of N. Zealand. As described 

 by Haast it was secured, along with Galaxias brevipin- 

 nis and Retropinna richardsonii, in the Otira stream, "where 

 that alpine torrent leaves its picturesque gorge." So like 

 Pseudaphritis for the Nototheniidae, this genus for the 

 Leptoscopidae is evidently a primitive one, from which 

 have radiated off one line of marine derivatives like Lepto- 

 scopus and Kathetostoma, from shores of New Zealand 

 and South Australia that have migrated northward 

 toward the tropics, and another line like Pleiiragramma 

 and some allies that have become antarctic types. Thus 

 Pleiiragramma antarcticiim is stated by Boulenger to occur 

 amid deep waters in 78° 35' south, the most southern habi- 

 tat for any known fish. 



We would conclude then that while the Galaxidae and 

 the Aplochitonidae were primitively freshwater American 

 — probably in earliest origin N. American — fishes that 

 gradually spread southward and then eastward to the 

 Australo-N. Zealand area, but remained wholly freshwater 

 in habitat, the Nototheniidae and Leptoscopidae were both 

 of Australo-N. Zealand origin. These seem to have mi- 

 grated westward, and in the act gave off shore and then 

 deep-sea derivatives, some of which reached even to the 

 Falklands and Chile, while others, before or after breaking 

 up of the Southern continent, migrated into the most 

 southern habitat now known for fishes. 



In brief summary the writer would now condense the 

 main conclusions of the present chapter, so far as these 

 pertain to fishes, as follows: 



I. The Galaxidae, Aplochitonidae, and some Cyclo- 

 stomata, as freshwater groups, show a geographical distri- 

 bution that is strikingly different from that of any other 

 family. This distribution suggests a possible continuous 

 land-connection from Chile, Fuegia, and the Falklands to 

 Tristan, the Cape, Kerguelen, and thence to Tasmania, Aus- 

 tralia, New Zealand and New Caledonia. 



