THE COMMON SEPIA. 41 



consequently, in the slug they are very small. But the 

 Cuttle needs strong and acute sight, and accordingly the 

 eyes are very large, and are placed upon two prominences, 

 one on either side of the head. These eyes can be seen 

 by referring to the figure of the Octopus on page 32. 



Next, we come to the mode of progression. Some of 

 the Cuttles can swim slowly by flapping the arms up and 



EGGS OF SEPIA. 



down. All of them can crawl by means of the arms, 

 affixing and relaxing the suckers as they advance. 



But their chief mode of progress is exactly the same 

 as that which is employed by the larva of the dragon-fly 

 and copied by man in the rocket. Water is taken into 

 a cavity within the body, and expelled with greater or 

 less force according to the will of the animal. At every 

 respiration, the water is taken into the cavity and 

 expelled through a tube called the " siphon." This 

 siphon can be seen in the figure of the Sepia on page 38. 



