CEPHALOPODA. 203 



very strong even after death, the animal can in an 

 instant loose its grasp, and retire in case of danger, 

 by simply pushing forward the piston and filling 

 the vacuum. The power with which these arms are 

 endowed, and the strength of the sharp and horny 

 beak, render the Cephalopoda truly formidable op- 

 ponents, especially as they are carnivorous, and their 

 courage and cunning are equal to their rapacity. 



These arms are not only prehensile weapons, but 

 act as feet, the animal crawling upon them with 

 the beak towards the ground and the body elevated, 

 with a vacillating motion, as might be imagined 

 from the flexible nature of the supports.* By the 

 broad disk formed by the union of their bases, the 

 animal is also enabled to swim with considerable 

 facility, but in a backward direction. Two gills, 

 resembling fern-leaves, are placed within the sac, 

 which, receiving water through a valve, eject it 

 through a funnel-shaped aperture situated at the 

 back of the head. So forcibly is the respired water 

 thus expelled, that it is one of the ordinary means 

 of motion, the jets serving to dart the animal by 

 successive jerks backward through the sea. The 

 blood purified in these gills, is carried to two hearts, 

 one on each side, and from thence to a third central 

 heart, whence it is distributed through the arteries 

 of the body. One of the most curious circumstances 

 connected with the economy of the Cephalopoda, is 

 the secretion of a peculiar fluid of a most intense 

 blackness, lodged in a vessel, variously situated in 

 * See the figure of the Poulpe, at the head of this Class. 



