140 AXXALS XEW YORK ACADEMY OF SCIEyCES 



China : Ochyrocera. Pacitic coast states. Mexico. Antilles, Venezuela, 

 Brazil, Ceylon and tropical Asia; and Physocychis, California, Arizona, 

 and Xew Mexico to Colombia, Gniana, Antilles, Africa and tropical Asia. 

 All of these are on this particular hypothetical land mass and not else- 

 where, as far as is known, except possibly several Peruvian or Brazilian 

 localities. They were picked in a rather random fashion and only Antil- 

 lean genera were included. Taking the world as a whole tlie list could 

 be increased beyond the patience of the reader, but what would it prove ? 

 In general, it proves that it is possible to select a long list of genera and 

 even some species which accord with a certain hypothetical land mass. 

 In particular, the tropical parts of the area selected here includes some 

 of the most important preserves of ancient types. We may leave poly- 

 phyletic origin of genera out of account not only because its occurrence 

 is unproven but because it would not influence the case since a similar 

 base from which to get the separate origins would be required and hence 

 the problem would be merely restated, not changed. We have then to 

 decide as to which is more reasonable: (a) forms migrated over this 

 hypothetical land mass, which crosses the Indian Ocean and the Atlantic 

 at the Equator, and then died out or have not been found except in cer- 

 tain favored spots on this mass; or (b) forms spread over land which 

 now exists and, if you please, the shorter land connections but not the 

 oceanic ones, and have died out or have not been found except in certain 

 favored spots. A very readable and fair summary of the arguments in 

 favor of the first alternative is given in Scharff's •'Distribution and 

 Origin of Life in America."' He also favors a second Atlantic land mass 

 running from the Antilles to the Mediterranean region with an offshoot 

 to Bermuda and Xova Scotia. A list of spiders may be compiled from 

 the taxonomic part of this or other papers which will accord with this 

 bridge. The bridge was supposed to have existed in early Tertiary and 

 to have also connected northeastern America by way of the Great Lake 

 and Eocky ^Mountain regions with the southern tip of South America. 

 Most of South America was under water; eastern Brazil and part of the 

 present Atlantic bed formed a large island, while pan of Ecuador and 

 Peru formed the tip of a peninsula from the main land mass which lay 

 in what is now the Pacific and included the Galapagos, a strip running 

 across the middle of Central America to the Antilles, and in its north- 

 western sweep reached from California to Hawaii, but just before it got 

 to western Canada it turiied west, missed Alaska and connected up with 

 Asia, The thing is ratlier complicated but certain spiders might have 

 traveled the route. Xote in this connection that several genera and 

 groups of genera are known from noi-theastern Xorth America and Pata- 



