308 FUNCTIONS AND INSTINCTS. 



is thought to have been taken from a large 

 cuttle-fish half a league in circumference, so 

 as to be mistaken for floating islands, yet they 

 are really as tremendous animals, their size 

 considered, as any that Providence has com- 

 missioned to keep within due limits the popu- 

 lace of the waters. 



One of their most remarkable and unique 

 features, is the manner in which circulation 

 takes place in them. They have three hearts ; 

 the principal one, seated in the middle, sends 

 the blood through the arteries : the blood re- 

 turns by a vena cava, which dividing into two 

 branches, carries it to the two lateral hearts, 

 each of which sends it to the gills for oxygena- 

 tion, whence it returns again by the intermediate 

 heart. 



The Octopus, called by the French writers 

 the Poulpe, probably a contraction of polype, 

 differs from the common cuttle-fish, having 

 neither the arms nor long tentacles of that 

 animal, and instead of the large heavy bone 

 has only two small cartilages. This different 

 structure is rendered necessary by the difference 

 in their habits. The body of the octopus is 

 small, and it has legs sometimes a foot and 

 a half in length, with about two hundred and 

 forty suckers on each leg, arranged, except near 

 the mouth, in a double series ; so that it walks 

 \\ ith ease. They are often out of the water, 



