710 , JOHN HEWITT. 



the distribution may perhaps be adequately explained through 

 the agency of winds, especially if the species inhabiting remote 

 and isolated areas prove to be absolutely identical. Yet, one 

 is tempted to correlate the positive facts now known with 

 those presented by such groups as the Migine spiders, which 

 have been recorded from the following regions : Southern 

 Africa, Madagascar, New Zealand, Australia, Tasmania, and 

 Chili ; in the Migidse, at any rate, it is veiy improbable that 

 winds are of any importance as factors in the dispersal of 

 species. 



Addendum, Dece77iher, 1916. — Since the above account was 

 written, I have received a further note from Mr. Hogg 

 relating to the characters of the adult female. He considers 

 that the features of the epigyne will distinguish africanus 

 from piscator, but adds that the smallness of the difference 

 is certainly remarkable. 



With regard to the mode of distribution of these creatures, 

 their occurrence amongst entangled seaweeds at low water 

 seems to point to the possibility of passive dispersal on float- 

 ing seaweeds. I am indebted to Mr. W.Tyson, the authointy 

 on South African seaweeds, for some important information 

 bearing on this question. Briefly stated, the main facts are 

 as follows : In the sour.h of the Indian Ocean is a strong- 

 western equatorial current which meets the east coasts of 

 Madagascar and of the mainland, and is deflected south- 

 wards, gradually diminishing in intensity as it approaches 

 Cape Agulhas. There is also a fairly constant antarctic 

 current passing in a south-easterly direction from the Cape 

 to Australia ; this divides into two portions, one running 

 along the south coast of Australia, the other turning north- 

 wards into the equatorial region and eventually entering the 

 western equatorial current. Certain facts of distribution of 

 seaweeds are most readily explained on the assumption of 

 dispersal through oceanic current agency. Many species at 

 the Cape are recorded only from there and from Australia. 

 And again, many tropical and subtropical marine algas are 



