354. Geographical Distribution of Crustacea. 
is a temperature of 83° in July, and in the Yellow Sea, of 78° 
to 80°. But such northward migrations as are thus favored, are 
only for the season; the cold currents of the winter months de- 
stroy all such adventurers, except the individuals of some hardier 
species that belong to the seas or have a wide range in distribu- 
Sea-shore Crustacea are not in themselves migratory, and 
are thus unlike many species of fish. Even the swimming Por- 
tunidee are not known voluntarily to change their latitudes with 
the season. 
The following isa me recapitulation of the more prominent 
~_ bearing on these 
e distribution of individuals of many species through 
he shied miles in the Torrid zone of the Oriental seas. 
2. The very sparing distribution of Oriental species in Occi- 
dental seas. 
3. The ae total absence of Oriental species from the west 
coast of Americ 
a deol wie distribution within certain latitudes of the 
species we have called cosmopolites 
5. The occurrence of closely allied genera at the Hawaiian 
Islands and in the Japan seas. 
. The occurrence of the same subtorrid species at the Ha- 
waiian Islands and at Port Natal, South Africa, and not in the 
Torrid zone insgemmpcinte; as Kraussia rugulosa and Galene na- 
roe 
The occurrence of identical species in the Japan seas and 
at Port Natal. 
8. The occurrence of the same species (Plagusia tomentosa) 
in South Africa, New Zealand, and Valparaiso; and the occur- 
rence of a second species (Cancer Edwardsii (?)) at New “Zeal- 
- and Valparaiso. 
. The occurrence of closely allied species (as species of Am- 
has and Ozius) in New South Wales and Chili. 
The occurrence of the same species in the Japan seas and 
aA Mediterranean, and of several identical genera. 
The occurrence of a large number of identical species in 
on British seas and the Mediterranean ; and also in these seas 
and about the Canary Islands. 
12. The occurrence of closely ai if site identical, species 
(as of Palemon) in New Zealan the seas also 
of certain genera that. are elsewhere ecaiierig British, or com- 
mon only to Britain and Amer 
13, An identity in se ocelec of Eastern and Western 
Ameri 
: The following are the conclusions to which we are led by the 
facts.— 
ete Moe WERE e en Reg 
