e. o. 
i. Geographical Distribution of C'rustacea. 3 
"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. 
The 'l'ables are in two series. 'lThe first contains for each 
genus of Crustacea the number of species according 1o present 
knowledege in each temperature Region or Sub-zone.* 'Tl'he sec- 
ond, the number for each genus in each G'eographical Province. 
We proceed with a summary of the results presented in the 
first series of the 'l'ables. 
I. BRACHYURA. 
BEIC TET 
S : s S23 Emsg| - - 
ENNEENOUNE. 205 05 9o E. | SEEN S ute us ou os TEL T Los 
Maioidea, -  -  -  - |89| 57| 122| 85| 27 | 21| 16 | 14 | 92 || 3 (2) 
Cancroidea - T0 - |157112|229/| 22| 25 | 28| 25 | 8 | 69 | 3(3) 
Grapsoidea, - - -'»- |72| 88|1381| 21! 14| 27 | 10| 9 | 63 
.| Leucosoidea, - E £e s9 es 4s 1L|] 8].b5| S4 34 24 
Corystoidea, - - 3 2d won tees av mim ar176 r^ eno 
348129031 585! 911 "81 'I8' 601 39 264 
'his table contains the number of species of the orders of 
Brachyura, according to present knowledge, in each Region and 
Zone. 
"The following general facts or conclusions may be deduced 
from the 'T'ables of the Brachyura. 
L. 'T'he line of division, separating the. 'T'orrid and ''emperate 
zones of ocean temperature, following the 1socryme 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 'l'orrid and Subtorrid Re- 
gions (the 'T'orrid zone,) there are over one hundred now known to 
be common to the two. But of the two hundred and sixty-four 
in the ''emperate Regions, only thirty-four occur in the 'T'orrid 
zone. A large number of genera, containing more than a single 
- known species, are confined wholly to the 'l'orrid zone: such are 
Micippa (5 species), Menazthius (9), Huenia (4), Parthenope (3), 
Atergatis (17), Carpilius (13), all the Chiorodinze, including forty- 
nine species, nearly all the Eriphing, including eighteen species, 
Charybdis (15). At the same time, the species of the 'T'orrid 
and Subtorrid Regions are in many cases equally numerous. Of 
species of Charybdis, eleven species occur in each of these Re- 
gions; of the Carpilii, eleven are reported from the Subtorrid and 
but five from the 'T'orrid ; of the Mensthii, five are found in the 
'T'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 
nearer the equator. But this error will diminish the number of species regarded as 
peculiar to the colder regions, and if eliminated, the following conclusions would be 
still more strongly sustained. 
