1903.] GEOGRAPHICAL DISTRIBUTION OF SPIDERS. 353 
Mauritius ; Sasonichus, 8. India; Sipalolasma and Plagio- 
bothrus, Ceylon; Hneyocrypta, Singapore to Australia ; 
Barychelus, New Caledonia; Jdioctis, Upolu; fdiommata 
and TZrittame, Australia; Psalistops, Stothis, Huthycalus, 
Epipedesis, Cosmopelma, Trichopelma, ? Acanthogonatus, 
Homeoplacis, Idiophthalma, Stropheus, Cyrtogranmommna, 
Neotropical Region. 
b. Diplothele : Diplothele, India and Ceylon; Sorsythula, 
Madagascar. 
c. Sasones: Sason, Seychelles, Maldives, Ceylon, India, and 
Celebes; ? Rianws, Pinang. 
The existence of a primitive type, Leptopelma, in the Medi- 
terranean area, and the entire absence of the group from the 
Sonoran Region and from China, suggest its origin in the western 
part of the Old World. Moreover, the presence of genera in 
Sokotra, Mauritius, Madagascar, and all over the Ethiopian 
Region attests a southern migration at a very early date, 
Similarly, the extension of the group over the Oriental Region, 
from India to Australia, suggests a perhaps contemporaneous move- 
ment in a south-easterly direction over the area in question, after 
the isolation of New Zealand. Again, the absence of genera of this 
family from the Sonoran Region, coupled with the relationship 
between the Mediterranean genus Leptopelma and many of the 
Neotropical types on the one hand, and between the remainder of 
the latter and the Tropical African genera on the other, points to 
a transatlantic connection between Africa and Europe and South 
America. At the same time, the possibility of a migration into 
South America from Australia across the area of the Pacific must 
be borne in mind, 
In the absence of evidence to the contrary, the genus Sason, 
specialised both in structure and habits, may be regarded as 
having arisen from a primitive type in the area it at present 
occupies. That this must have taken place in very early times, before 
the severance of the Seychelles from India and Ceylon, w ould be 
an unavoidable conclusion, were we sure of the distinctness of the 
Seychellesian from the Ceylonese species. But the occurrence 
of one of the Ceylonese species in the Maldives proves, I think, 
artificial introduction into that Archipelago; and the same expla- 
nation may apply to the presence of the genus in the Seychelles, 
One other point of interest remains, and that is the unques- 
tionably close relationship that obtains between the Indian and 
Ceylonese genus Diplothele and the Mascarene Forsythula, the latter 
being a more specialised type. This is almost the only undoubted 
case of similarity between the faunas of Madagascar and India 
that the Mygalomorphe supply. 
Family AvICULARIIDS. 
The distribution of this family is most instructive. 
The heterogeneous group of genera associated together as 
9% 
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