PARTS OF ANIMALS, IV. ix.-x. 



action is to draw flesh and yielding substances, as 

 follows. First they encircle the object while they 

 are still relaxed ; then they contract, and by so doing 

 compress and hold fast the whole of whatever is in 

 contact Avith their inner surface. 



So, as these creatures have nothing else with which 

 to convey objects to the mouth except the feet (in 

 some species) and the probosces (in others), they 

 possess these organs in lieu of hands to serve them 

 as weapons and generally to assist them otherwise. 



All these creatures have two rows of suckers, except 

 a certain kind of Octopus, and these have only one, 

 because owing to their length and slimness they are 

 so narrow that they cannot possibly have another. 

 Thus they have the one row only, not because this 

 arrangement is the best, but because it is necessitated 

 by the particular and specific character of their being. 



All these animals have a fin which forms a circle 

 round the sac. In most of them it is a closed and con- 

 tinuous circle, as it is in the large Calamaries (ieutki), 

 while in the smaller ones called teuthides it is quite 

 wide (not narrow as in the Sepias and Octopuses), 

 and furthermore it begins at the middle and does not 

 go round the whole \vay. They have this fin to 

 enable them to swim and to steer their course, and 

 it answers to a bird's tail-feathers and a fish's tail- 

 fin. In the Octopuses this fin is extremely small and 

 insignificant because their body is small and can 

 be steered well enough by means of the feet. 



This brings to an end our description of the internal 

 and external parts of the Insects, the Crustacea, the 

 Testacea, and the Cephalopods. 



X. ΝοΛν we must go back and begin again with 



363 



