Geographical Distribution of Crustacea. 315 
The reader is referred to the former paper and map for other 
details, where the Zoological Provinces in these zones are laid 
down, and explained. 
he ‘lables are in two series. -The first contains for each 
genus of Crustacea the number of species according to present 
nowledge in each temperature Region or Sub-zone. he sec- 
_ ond, the number for each genus in each Geographical Province. 
We proceed with a summary of the results presented in the 
first series of the Tables. 
I. BRACHYURA. 















wt Pe Pie Bre Gee ye 
2/5 eal og eleelee 2/55 < 
S/S 1s S82) 8 /Sese] 4 /sei =e 
Bia |ge) Fb) & |agog) ass) & 
6s le Hse Ss Ie | ee Me 
aioidea, - = = | 82} 57] 122) 85) 27) 21] 16) 14 | 92 |] 3(2) 
Cancroidea- - - = .|157/112) 229] 22| 25] 23] 25) 8 | 69 |] 3(3 
rapsoidea,- - - - ‘| 72} 88/181) 21] 14| 27] 10| 9 | 63 
peers = SS oY ge a ey) f1) 6T | S| «eee 
Girfiioides, = =. Lethe SP ph ee) cia es 2 6 16 Hate 
3481293! 535! 91! 781 78! 60! 39 264 



This table contains the number of species of the orders of 
pany, according to present knowledge, in each Region and 
one. 
The following general facts or conclusions may be deduced 
from the Tables of the Brachyura. 
- The line of division, separating the Torrid and Temperate 
Zones of ocean temperature, following the isocryme of 68° or the 
outer limit of coral reef seas, marks a grand boundary in organic 
life, well exemplified in Crustacean species. Out of the five 
hundred and thirty-five species of the Torrid and Subtorrid Re- 
gions (the Torrid zone, ) there are over one hundred now known to 
Se common to the two. But of the two hundred and sixty-four 
i the Temperate Regions, only thirty-four occur in the ‘Torrid 
Zone. A large number of genera, containing more than a single 
known species, are confined wholly to the Torrid zone: such are 
Micippa (5 species), Menethius (9), Huenia (4), Parthenope (3), 
Atergatis (17), Carpilius (13), all the Chlorodin, inelnding forty- 
nine species, nearly all the Eriphine, including eighteen species, 
Charybdis (15). At the same time, the species of the Torrid 
and Subtorrid Regions are in many cases equally numerous. 
Species of Charybdis, eleven species occur in each of these Re- 
gions; of the Carpilii, eleven are reported from the Subtorrid and 
bat five from the Torrid; of the Menzthii, five are forind in the 
orrid Region, and six in the Subtorrid; only two being common 
to both. ‘These proportions may be much varied by future in- 
* Since the ocean’s waters decrease in temperature as we descend in depth, there 
Will be some error in the tables from the cold water species thus passing into regions 
Rearer the equator. But this error will diminish the number of species regarded as 
regi usions would 
Peculiar to the cold and if eliminated, the following conch be 
still more strongly 
