178 BULLETIN OF THE BUREAU OF FISHERIES. 



In traveling over the bottom in search of prey the lobster walks nimbly upon the 

 tips of its slender legs, which are provided with brushes of sensitive hairs. The large 

 claws are directed forward, a position which offers the least resistance to the water, or 

 when at rest are held somewhat obliquely, their tips touching the bottom, while the 

 long sensitive "feelers," or antennae, sweep back and forth continually to give warning 

 of a foe or of objects which its other sense organs fail to detect. In exploring its feeding 

 grounds the movement of the body is chiefly maintained by the swimmerets, or pleopods, 

 which spring from beneath the tail in the form of a double bank of paddles on either 

 side. The swimmeret consists of a short stalk and two flexible blades, which beat 

 rythmically with a backward stroke, and thus impel the animal forward even without 

 the aid of the ambulatory legs. Each blade is further garnished with a fringe of long 

 and strong hairs or setae, which add to its efficiency as a rowing organ, and certain of 

 which in the female catch and hold the egg glue by which her progeny, in the form of 

 thousands of eggs, are tethered to her body. 



The most primitive^sense of animals being that of touch, it is not surprising to find 

 • tactile organs widely distributed over the body of this crustacean. As will be seen 

 later, they occur by thousands in the form of tufts and fringes of hair-like setae on the 

 legs and free margins of the shell, and in any part subject to frequent contact either 

 with the body itself, with its food, or the ocean floor. It will also appear that instead 

 of being incased in a solid, impenetrable armor, the crustacean can receive stimuli and 

 impressions from without as readily as if it possessed a soft and delicate skin. 



When an enemy appears, or the lobster is suddenly surprised and cornered, it will 

 immediately strike an attitude of defense. Raising itself on the tips of its walking 

 legs, it lifts its powerful claws over its head, after the manner of a boxer, and, striking 

 the offending object, endeavors to crush and tear it to pieces. 



When transferred from sea to land the lobster can only crawl in its vain attempts 

 to walk, owing to the great weight of its body, which the slender legs are unable to 

 sugtaiu. If turned on its back its discomfort is immediately shown by attempts to 

 right itself, which are usually successful. When taken directly from the water and 

 left to its own devices on the beach, I have seen it strike out by the nearest path to the 

 sea with as keen a sense of direction as a turtle shows on land. It should be stated, 

 however, that this experiment was tried only within short distances from the water. 



By far the most powerful organ of locomotion in the lobster is its "tail," called 

 also the "abdomen" (terms borrowed from vertebrate anatomy), and the "pleon." 

 By the rapid flexion of this muscular tail, aided by its terminal fan, the lobster shoots 

 backward through the water with astonishing rapidity, going, according to one observer, 

 25 feet in less than a s econd . If tossed into the water, the animal quickly rights itself, 

 and with one or two vigorous flexions of the tail makes quickly for the bottom as if 

 sliding down an inclined plane. 



On calm summer evenings toward sundown lobsters are often seen close to shore, 

 lying on little patches of sand or in eel grass, awaiting their chance to seize a passing 

 fish or crab. When alarmed, they assume the defensive attitude; but press them close, 



