48 American Se ash ells 



When it is darting rapidly, the lobes of the caudal fin are closely wrapped 

 around the body, and the arms are held tightly together to form a streamlined 

 outline. Except when attacking or escaping, the squid swims less strenuously, 

 using the caudal fin as a balancing organ. 



There are few sights as interesting as that of squid engaged in capturing 

 and devouring young mackerel. During the summer this chase may be 

 observed from certain wharves in New England. In attacking mackerel 

 the squid darts backward among the fish with the velocity of an arrow, and 

 then turns obliquely to one side and seizes a fish, which is almost instantly 

 killed by a bite in the back of the neck by the squid's sharp beak. The bite 

 is always made in the same place, cutting out a triangular piece of flesh, and 

 is deep enough to penetrate to the spinal cord. The attacks are not always 

 successful and may be repeated a dozen times before one of the wary fish 

 can be caught. Between attacks a squid may suddenly drop to the bottom 

 and, resting on the sand, change its color to that of the sand so perfectly 

 as to be almost invisible. Ordinarily, when swimming, it is thickly spotted 

 with red and brown but, when darting among the mackerel, it appears trans- 

 lucent and pale. The schools of young mackerel often move close to shore 

 where the water is shallow and offers more protection. In their eagerness 

 to capture fish, the squid frequently force themselves up on the beach where 

 they perish by the hundreds. At such times they often discharge their ink 

 in large quantities. 



Many species of octopuses and squid possess an ink sac and, in moments 

 of great excitation they may expel a large cloud of black or brown liquid 

 through the siphon. The ink is of a caustic nature and, in addition to its 

 use as a "smoke screen," it is believed to be distasteful to hungry fish. Two 

 sources of sepia ink are a species of squid found along the southeastern 

 coast of China and another found in the Mediterranean Sea. 



Many geologic eras ago the cephalopods possessed large and showy shells. 

 Today, however, shells produced by this class are a rarity. The most spec- 

 tacular shell is found produced by the Indo-Pacific Chambered Nautilus, 

 Naiitihis p077ipiliiis. On our shores, the small, white, spirally coiled shell of 

 Spirilla is frequently encountered on southern beaches. The three-inch-long 

 Spirula squid which produces this shell is a denizen of deep water. In other 

 squid the internal shell has been reduced to a simple slab of chalky material 

 (the cuttlefish bone fed to canaries) or, in the case of the Loligo squid, to 

 a thin, elongate shaft of transparent, horny material. 



By an odd turn of fate, squid are heavily preyed upon by adult cod, 

 mackerel and other fish, and no doubt some young mackerel which have 

 escaped by a tentacle's breadth have lived to devour later their would-be 

 assassins. Squid are taken in large quantities in nets and weirs each year, and 

 they constitute one of the main fish baits on the Grand Banks. They are 



