l8o BUI^LETIN OF THE BUREAU OF FISHERIES. 



crevice, or in its burrow in the mud, it waits until the victim is within reach of its 

 claws. Though far less active and keen witted than many of the higher crabs, and 

 sedentary in the sense of being restricted in its range, it is sluggish only at the period 

 of the molt or in very cold weather. The sense of hearing is probably absent and that 

 of sight far from acute, but this animal possesses a keen sense of touch and smell, possibly 

 a sense of taste, and is quite sensitive to changes of temperature and light (see p. 184). 



MIGRATORY INSTINCTS. 



Adult lobsters never migrate up and down the coast at definite periods or in con- 

 siderable numbers in any degree comparable to the semiannual movements of many 

 fishes and birds; in April and May, however, they come in toward the shore, and again 

 in fall retire to deeper water. Such migratory instincts as they possess are of a very 

 diffuse type and are far from being generally displayed. The abundance of food and 

 periodic necessity of molting and laying eggs, and the temperature of the water, mav 

 one and all enter with more or less force into bring ing a bout local and restricted move- 

 ments. When the question of food is paramount, lobsters will pass the winter in con- 

 siderable numbers in the shallow waters of harbors, but usually onlyon a rocky botto m 

 where food is to be found- The pytent of their journeys is influenced by the slope o f 

 the bottom and t hp Hppfti nf watpr, as wp U as by the nature of the bottom itself, and 

 varies in different sections of the coast as well as at the same point in diffe rent seas ons. 



Movements of tagged lobsters. — In order to test the extent and rapidity of the adult 

 lobster's movements along the coast, as well as to and from deep water, some interesting 

 experiments in tagging lobsters have been made by Bumpus {43) at Woods Hole, Mass., 

 Mead and WilUams {193) at Wickford, R. I., and by Meek (316) and Appelldf {303) in 

 Europe. 



In the summer of 1898 Bumpus tagged 479 lobsters from which eggs had been 

 removed, and liberated them at various points about Woods Hole. Seventy-six of 

 these were recaptured and the tags returned for identification. The valuable data thus 

 obtained showed a great variation in the "migratory" impulse and remarkable rapidity 

 of movement in individual cases. Some had not strayed far after gaining their freedom 

 for from 3 to 4 weeks, being recaptured near the points where they had been set free, 

 while others had moved at the daily rate of a mile for a period of 10 to 12 days. One 

 of them which had been freed at Woods Hole on July 2 entered a trap at Cuttyhunk 

 Island, 1 2_ miles to the southwest, on July 13, having covered this distance in 11 days. 

 It does not seem pfbbabtelhat such sporadic movements are determined by the search 

 for more abundant food, or for more favorable conditions as regards the temperature 

 and depth of the water or character of the bottom, but are to be set down to individual 

 initiative and general restlessness of behavior. In this connection it would be interest- 

 ing to learn whether the more sedentary or the more active individuals had showed 

 any evidences of preparation for the molt, which is due in female lobsters shortly 

 after the hatching of the eggs (middle May to middle July at Woods Hole). 



Tagging experiments were undertaken by Mead in the summer of 1902 and 1903 

 at Wickford. Of the 16 released in the first season, the most enterprising traveler had 



