The Common Squids 



lumps of clear, gleaming semi-fluid jelly. The eyes a brilliant 

 green, and the skin freckled over with spots of red, which be- 

 came much deeper when the creature was handled. A dozen 

 were obtained with difficulty by sweeps of a dip net for study in 

 the laboratory aquarium. Here they not only blushed when 

 disturbed, but spouted black ink in quantities corresponding to 

 their sizes. 



Specimens a foot long are interesting tenants of an aqua- 

 rium. Poke the placid cephalopod with a stick and he blushes 

 all over with freckles of pale red. Now he shrinks behind a gray 

 stone, and his ruddy colour has turned to gray. Or sinking to 

 the sandy floor of the tank he may seem to flow over the surface, 

 a yellowish mass, scarcely visible. 



The reason for these chameleon changes has been discovered. 

 The skin has several series of pigment spots, globular in shape, 

 each enclosed in a membrane, which is supplied with a double 

 set of muscles, and nerves connecting all with central ganglia 

 which control them. Each speck of pigment is flattened into 

 quite a large patch of colour by the contraction of the muscles 

 attached to its equator — all pulling outward at the same time. 

 When the red spots are called out, the gray and other sets are 

 inactive, and the squid blushes violently. This is the usual 

 colour exhibited in the aquarium. 



The capture of food is the work of the horny, cup-shaped 

 disks that crowd the inner faces of the arms and the clubs of the 

 tentacles. In the bottom of the cup is a flat piston on a stout 

 rod of muscle. When the disk is applied to any object the mus- 

 cular lips and saw-toothed cartilage make an air-tight contact, 

 for the piston is raised, forming a vacuum against which the air 

 outside presses powerfully. These sucking disks are attached 

 to the arms by flexible stalks. An object seized is at once held 

 by as many of these suckers as can get hold. The arms bend 

 and shorten to bring the prey to the mouth, the lips fall back, 

 ths beak rises up and tears the object into pieces, bolting them 

 as large as possible. 



In the breeding season the fourth arm of the left side be- 

 comes hectocotylised at the tip in the adult males. The suckers 

 in part are replaced by papillae. The spermatophores are car- 

 ried in this arm from the time they are formed until time for 

 fertilising the ova. A single female is said to produce forty 



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