ORDER I. DECAPODA. 255 
The order is divided into two families — Brachyura (Short Tails), and 
Macrua (Long Tails). The first comprises the genus 
Cancer. —The Crabs. The distinguishing characteristics of the genus 
are, the tail shorter than the thorax, triangular in the male, and rounded in 
the female; small antenne; the peduncles of the eyes larger than in the 
second family ; and branchiw arranged in a single row in pyramidal plates, 
composed of a great number of minute leaflets spread one upon the other. 
Crabs are completely wanting in the Ingh northern seas ; their number 
increases with the warmer temperature of the waters, and attains its maxi- 
mum in the tropical zone. Here we find the most remarkable and various 
forms ; here they attain a size unknown in our seas; and here they do not, 
as with us, inhabit solely the salt waters, but also people the brooks and 
rivers, or even constantly sojourn on land; as, for instance, the Thelphuse 
and Geearcini. There are even some species of land crabs that suffocate 
when dipped into water. They breathe, indeed, through branchiw, but the 
small quantity of oxygen dissolved in water does not suffice for the wants 
of their active respiration. They generally live in the shades of the damp 
forests, often at a great distance from the sea, concealing themselves in holes. 
At breeding-time they generally seek the shore for the purpose of washing 
off their spawn, and depositing it in the sand; and no obstruction will then 
make them deviate from the straight path. 
They feed on vegetable substances, and are reckoned very excellent food. 
When taken, they will seize the person’s finger with their claw, and en- 
deavor to escape, leaving the claw behind, which, for some time after it 
has been separated from the body, continues to give the finger a friendly 
squeeze. In the dusk of the evening they quit their holes, and may then 
be seen running about with great swiftness. 
C. Pagurus. —This is the common edible crab. It has a very broad 
shell, and arched for a great distance along the sides; the claws are large, 
and the fingers are black, armed with obtuse points. It is captured by 
sinking pots or baskets, properly prepared and baited, to a considerable 
depth in the ocean along the rocky coast. It is the most abundant in the 
summer. At low tide these crabs are found among the rocks in pairs, and 
if the male be taken away, another will be found in its place at the next 
recess of the tide. In winter they either burrow in the sand or withdraw to 
deeper waters. 
Portunas. —The Portuni have the ordinary crab-like form, but the ocu- 
Jar peduncles are very short, and the terminal joint of the hind legs is much 
narrower than in the Paguri. They are abundant in the Venetian lagoons, 
and the catching of them affords a profitable employment to the inhabitants 
of those swampy regions. Whole cargoes are sent to Istria, where they are 
