ON CRUSTACEA. 
309 
tence, must have seen them under this particular circum- 
stance. According to the report of the last-mentioned writer, 
the pagurus, which has for a short time quitted its shell, runs 
fast, when any danger threatens, back to the place where it 
has left it, re-enters it quickly, going backwards, endeavours 
to close its entrance against the enemy, and defends itself with 
its claws. According to him, its bite produces for two days 
the same effect as the sting of the scorpion ; but the pincers 
of the pagurus, being similar to those of the other decapod 
Crustacea, cannot act in a different manner, and like them can 
produce nothing but a pressure, more or less strong, on the 
body which they have seized. 
Some authors have spoken of the combats in which the 
paguri engage for the possession of a shell : it does not always 
fall to the lot of the conqueror ; for, during the struggle, ano- 
ther individual has sometimes the address to possess himself 
of the object in dispute. 
Other Crustacea, wdiich are placed in the same genus, but 
little known, and some of which perhaps do not belong to it, 
have no need of shells, and make their retreat in the holes of 
rocks, in sponges, in the tubes of the serpulse ; others remain, 
as is reported, in the sand. 
Like the other decapod Crustacea, the females of the paguri 
cany their eggs under the tail, and attached to small barbed 
nets, or to the false feet ; but it appears that these oviferous 
appendages occupy but one of the sides of the tail. Accord- 
ing to M. Risso, these animals lay eggs two or three times a 
year, and always approach the sea shore where a collection of 
little empty shells is accumulated, so that the young ones may 
choose, as soon as they are born, a suitable retirement. After 
their first growth, they possess themselves of columbella), of 
tupiae, of fresh water shells, which have been carried into 
the sea ; afterwards, of buccina, of cerithise, and of rocks. 
Whether they walk upon the rocks outside the water, or draw 
