G'eographical Distribution of Crustacea. 5 
. If we examine into the subdivisions of the Maioidea and Can- 
eroidea, we shall find the difference between the two groups in 
distribution more strikingly brought out. We shall find, more- 
over, that both groups may be divided into a warm-water and 
cold-water section, as below. 
IL MAIOIDEA. 
l. COLD WATER OR TEMPERATE ZONE SECTION. 
Torrid Temperate 
species. species. 
1. Inachide, : à "A 10 
2. Maiidz, subfamilies, Aabinine, Maine; Pisine, Othonine, 15 35 
789. Eurypodid:e, : . : : : : ut T 
4. Leptopodidz, : : à , ; 1 1 8 
] T4 60 
2. WARM WATER OR TORRID ZONE SECTION. 
'Torrid. Temperate. 
1. Maiide, subfamilies TONO fepe Jupe 25 la 
9, Mithracidze, : : 11 6 
8. Tychide,  . : : : : : EL: 0 
4. Pericerids, ; : ; : : : 48 14 
5. Parthenopinea, : : : . . 4428 8 
6. Oncininea, : t : : : : 2 0 
104 81 
IL CANCROIDEA. 
l. TEMPERATE ZONE SECTION. 
* : 'Torrid. "Temperate. 
Cancridze, : : : : ; o 0 11 
Platyonychidee, : : : : : 2 (i 
Portunidz, subfamily Portuninc, : : : Ju 15 
Cyclinea, : : . 0 1l 
2 94 
2. TORRID ZONE SECTION. 
"lTorrid. "Temperate, 
Xanthidz, : : : ; : 1 .Is9 1 
Eriphide, . : : : 44 12 
Portunidz, excluding the Portuninc, : ; : . 82 7 
Podophthalmidse, : . : : : : 2 0 
22 35 
We have here two singular facts brought out. 
F'irst, that the cold-water section of the Cancroidea embraces 
those species that approach most nearly to the Corystoidea, and 
which we have elsewhere shown to be the /owest in grade of 
the Canerinea. All have the lax character of the outer maxilli- 
peds, which is a mark of degradation in the Corystoids; and the 
Cyclinea are still nearer that group. Many of the species more- 
over have the hind legs a swimming pair, another mark of degra- 
dation. 'lhe Corystoidea, as before shown, are two-thirds cold- 
water species. 
Second, that the cold-water section of the Maioidea contains 
. the species that are highest in grade, and largest in size. It is 
headed by the Macrocheira of Northern Japan, the king of all 
crabs, whose body is seventeen inches in length and a foot, broad ; 
