1903.] GEOGRAPHICAL DISTRIBUTION OF SPIDERS. 349 
Africa; Mierobatesia in tropical W. Africa; Stictogaster, Dessia, 
and Homostola in 8. Africa; Stenoterommata, Pselligmus, Neo- 
cteniza, Eucteniza, and Enrico in South and Central America ; 
Aptostichus and Actinowia in California ; and Myrmeciaphila in 
Virginia and Carolina. 
Bn Aganippe, differing from the preceding in the specialised 
arrangement of the eyes.—dAganippe, Blakistonia, Anidiops, 
Idiosoma—all confined to Australia. 
4, Aporoptychi, differing from the Cyrtauchenii in the 
enlargement of the labium and maxillee.—Aporoptychus and Lolo- 
stromus occur in tropical West Africa and South America ; 
Phrissecia, Pheoclita, Celidotopus, Phenothele, and Rhytidicolus 
in 8. America. 
Of the above mentioned groups, that of the Nemesiz is the 
only one that is represented at the present time in India, Mada- 
gascar, and New Zealand—a fact in keeping with its primitive 
status, and suggestive of an earlier migration into the Southern 
hemispheres. “Singularly enough, the group is unrepresented in 
North America. This and the fur ther facts that South Africa is 
the richest of the regions in number of genera, and that one of its 
genera, Hermacha, occurs also in Brazil, make it almost impossible 
to doubt that the group entered South America from South Africa. 
Again, since the group is also apparently absent from the whole 
of the area lying between India and Australia, we must look to 
South Africa, Madagascar, or South America as the source whence 
it entered Australia ; and since the Mascarene genus Genysa is 
said to be nearly allied to the Australian Arbanitis, Madagascar 
and §. Africa were perhaps the feeders to the Australian area. 
Since the Cyrtauchenii are specialised allies of the Nemesiz, 
and therefore later developed forms, it is interesting to note their 
apparent absence from Madagascar, India, Australia, and New 
Zealand, which indicates a later southern migration from the 
north. The following hypothesis seems to explain the facts of their 
distribution. In early Tertiary times the group was continuously 
distributed throughout Europe, Asia, and North America. In 
Eastern Asia it descended a short distance into Indo-Malaya after 
the severance of Australia, and penetrated Africa after the forma 
tion of the Mozambique Channel. Similarly from the Sonoran 
Region it passed into Central and South America, after the 
Pliocene union of the latter with North America. Whether any 
of the South-American fauna was derived from Africa or vice 
versa, there is no reliable evidence to show. 
If the Aganippe entered Australia from South-eastern Asia, 
it is strange that no related forms have been discovered in Austro- 
Malaysia. They may have come from South America or South 
Africa; but I am disposed to think that they have had an origin 
independent of the Cyrtauchenii in Australia from the Nemesiz, 
from which they differ practically only in the procurvature of the 
fovea—a feature which is known to have arisen more than once 
