32 STUDIES IN LIFE AND SENSE. 



must have been struck by the puffing and blowing movements of the 

 sack-like body, the nature of which excited Victor Hugo's imaginative 

 powers in the " Toilers of the Sea." The octopus is seen to inspire 

 and expire with great regularity. The soft body expands and con- 

 tracts rhythmically enough to excite a natural comparison between 

 its respiratory acts and our own. If we could dye the water so that 

 our eye could follow the currents which the octopus inhales and ex- 

 hales, we should perceive that at each inspiration the soft body ex- 

 pands, and water is drawn in two currents into the neck-openings. 

 These openings lead directly each, into a gill- chamber of the animal. 

 Here, enclosed in its own cavity, we find a plume-like gill. In its 

 nature, this structure is simply a mesh-work of blood-vessels, and 

 thus comes to resemble a lung in its essential features. Impure 

 blood that is, blood laden with the waste materials of the octopus- 

 body, with the products of the vital wear and tear is driven into 

 the gill on one side. Subjected to the action of the oxygen gas con- 

 tained in the water breathed in, the blood is purified. Its waste 

 materials are given forth to the water, and it is passed onwards out 

 of the gill on its way to the heart for recirculation throughout the 

 cuttlefish-frame. 



Breathing in oxygen entangled in the water is, therefore, in the 

 case of the cuttlefish, an analogous act to that seen in higher animals, 

 which inhale oxygen directly from the air. The octopus, however, 

 performs an expiratory act likewise. Placed below the head is a 

 short tube, named in zoological parlance the " funnel." When 

 cuttlefish inspiration has come to an end, expiration begins. The 

 body contracts, and the water, which a moment before was drawn 

 into the gill-chambers by the neck-openings, is expelled from the 

 " funnel." The openings of entrance are guarded by valves. These 

 close when expiration begins, and the water has no choice save to 

 find a forcible exit by the tube just named. So far, in octopus exis- 

 tence, it would seem as though there was no economy of power 

 exhibited in the act of breathing. Muscular action expands the soft 

 body, and muscular force contracts it. There is exhibited here a 

 plain difference between the octopus and the higher vertebrate. 



But the story of cuttlefish-economy is not yet completed. A 

 moment more and your octopus, which sat crouched in the bottom 

 of the tank, is seen to wing its way through the water. It skims like 

 a living rocket through the clear medium in which it lives, as if 

 impelled by some marvellous and invisible agency. The secret ol 

 this flight is the solution of cuttlefish-economy and reserve force. 

 So long as the resting mood prevails, the water used in breathing is 

 ejected slowly, or at least without any marked display of force. But 

 when locomotion has to be subserved, and when the cuttlefish 

 desires to swim, it propels itself through the water by aid of a 



