ORTMANN — DISTRIBUTION OF DECAPODS [April 3, 



less in that this connection is placed across the Antarctic conti- 

 nent, and this idea is chiefly supported by Hedley (1895, 1899), 

 von Ihering (1891, 1894), Osborn (1900), Pilsbry (1894), and 

 Ortmann (1901, 1902). 



While Pilsbry only generally expresses the opinion that the sup- 

 position of an old Antarctic continent connecting the respective 

 parts of the present southern continents would furnish the condi- 

 tions necessary for the explanation of the zoogeography of the 

 land-mollusks, and while Osborn only tries to give an approximate 

 idea of the mutual relations of these land-masses by pointing out 

 that a subsidence of the ocean level of a certain amount would 

 connect these parts, von Ihering (1894, p. 438) gives a more 

 detailed theory of this connect ion. He unites not only South 

 America over Antarctica with Australia, but continues this (Meso- 

 zoic) land mass beyond the Indo-Malaysian islands to east Asia, 

 thus including the Sino Australian continent discussed above. He 

 calls this vast continent by the name of Archinotis. 



As to the details of the special connection of Australia and South 

 America, Hedley's opinion is the most important ; according to 

 him (1895, p. 6), during Mesozoic and older Tertiary times a 

 stretch of land extended from Tasmania over the South Pole to 

 Terra del Fuego ; the shore line of this land (\ntarctica) formed a 

 wide gulf between Tasmania and Cape Horn, and approached the 

 Pole. This land-bridge, however, was not very solid, but was sub- 

 ject to various changes resulting in a repeated breaking up and 

 becoming reunited of the different parts. As regards New Zc-aland, 

 he believes that during the Tertiary time it was not directly con- 

 nect d with Antarctica. In another paper, however (1899, p. 399), 

 Hedley also assumes a connection of New Zealand with Antarc- 

 tica, but this was of an older date than that from Australia over 

 Tasmania to Antarctica, and consequently is to be placed in the 

 Mesozoic time. 



That Australia was once connected with Antarctica, especially 

 with what is now called Wilkes' and Victoria Land, can be imag- 

 ined as possible on tectonic grounds. Australia itself consists, 

 according to Suess (1868, p. 188 ff.), in its eastern part of a very 

 old range of mountains, running in a north-southerly direction; 

 its larger western part is an old Archaic and Palaeozoic plateau 

 (part of Gondwana Land). Both parts are fractured and cut off 

 toward the south, and the southern parts have disappeared ; a line 



