340 SEA MONSTERS UNMASKED. 



framework as they possess. In Sepia, the mantle-sac is 

 flattened horizontally all along its lateral edges so as to 

 form a pair of fins, which nearly surround the trunk. These 

 fins could never be used, as they are, to enable the animal 

 to poise itself delicately in the water by means of their 

 beautiful undulations, which I have often watched with 

 delight, if their attached edges were not kept in a straight 

 line on either side. Then, these ten-footed or ten-armed 

 genera have not, because they need them not, eight long, 

 strong and highly mobile arms like those of the octopus, nor 

 have they large suckers upon them. Whereas a great length 

 of reach is an advantage to the octopus, animals which are 

 purely swimmers, and which hunt and overtake their prey 

 by speed, would be impeded by having to drag after them 

 a bundle of stout, lengthy appendages trailing heavily 

 astern. Their eight pedal arms are short and comparatively 

 weak, though strong enough, in individuals such as are 

 regarded on our own coasts as fullgrown, to seize and hold 

 a fish or crustacean as strong as a good sized shore-crab. 

 But, as compensation for the shortness of the eight arms, they 

 are provided with two others more than three times the 

 length of the short ones. These are so slender that they 

 generally lie coiled up in a spiral cone in two pockets, one 

 on each side, just below the eye, when the animal is 

 quiescent, and are only seen when it takes its food. These 

 long, slender tentacular arms are expanded at their extre- 

 mity, and the inner surface of their enlarged part is studded 

 with suckers some of them larger in size than those on 

 the eight shorter arms. As the food of these swimmers 

 consists, of course, chiefly of fish, their sucking disks are 

 curiously modified for the better retention of a slippery 

 captive. A horny ring with a sharply serrated edge is im- 

 bedded in the outer circumference of each of them, and 



