352 Geographical Distribution of Crustacea. 
Seweme picta—Nat. and Jap. Dromia hirsutissima. ‘as _ and Haw. 
Sesarma affinis.—Nat. and Jap. Calappa spinosissima.— and Haw. 
Sracacia rugulosa,—Nat. oe: ee Doto sulcatus, Nat. ae R Sea. 
Galene natalensis.—Nat. a 
The species of us Bik while somewhat related to those 
of southeastern: Australia, have rather close relations to those of 
Chili, and also some resemblance to those of Britain. The gen- 
era Ozius, Hemigrapsus and Chasmagnathus are common to 
both New Zealand and the part of oe referred to. The 
ilowive genera characterize both Chili and North New Zea- 
and :—Cancer, Ozius, Cyclograpsus, chain and Beteus ; 
oo the Cancer Edwardsii and Plagusia tomentosa appear to be 
common to the two provinces, while the genus Cancer is not 
elsewhere known out of America and Northern Europe. Pale- 
mon affinis of the Bay of Islands, as Edwards observes, is hard- 
ly distinguishable from P. squilla of the coasts of France and 
belong rather to the cold temperate than subtemperate 
sities i the Australian and New Zealand seas. Portunus in- 
tegrifrons is reported from Tasmania (Yan. Diemens Land). 
Ozius joie Xantho of the British Chan 
he occurrence in New Zealand of this repressotatia of a 
cold water Xantho, of the Palemon affinis so near a European 
species, of Cancer and Portunus, which are found together only 
in British seas, shows a striking zoological relation between these 
antipodes—a relation plainly dependent on the similar insular 
character and oceanic temperature of the two regions, Britain 
and New Zea 
In the Soothe: Polar seas, the species have often a wide range, 
and probably pass from one ocean to the other through the Polar 
oceans. Thus Crangon boreas, Carcinas menas, Pagurus streb- 
lonyx, Hippolyte aculeatus, are not only found on opposite sides 
of the Atlantic, but also in the North Pacific. 
Origin of the Geographical Distribution of Crustacea. 
The origin of the existing distribution of species in this de- 
partment of zoology deserves attentive consideration. Two 
great causes are admitted by all, and the important question is, 
how far the influence of each has extended. The first, is origt- . 
nal local creations ; the second, migration. 
Under the first head, we may refer much that we have already 
said on the influence of temperature, and the restriction of spe- 
cies to particular temperature regions. It is not doubted that 
the species have been created in regions for which they are es- 
pecially Pea that their fitness for these regions involves an 
adaptation of structure thereto, and upon this adaptation, their 
