Chapter XIV.— SUMMARY OF OBSERVATIONS. 
GENERAL REVIEW OF THE LIFE-HISTORY OF THE LOBSTER. 
1 will now give a brief summary of the most important observations which have 
been detailed in this work, emphasizing in particular those facts which bear upon the 
problem of the artificial propagation of the lobster. 
(1) Distribution . — The geographical range of the lobster covers about 20 degrees of 
north latitude, from the thirty-fifth to the fifty-second parallel, and includes a strip 
of the Atlantic Ocean 1,300 miles long and from 30 to 50 miles wide. Its vertical dis- 
tribution varies from 1 to upward of 100 fathoms. The most northern point at which 
its capture has been recorded is Henley Harbor, Labrador ; the most southern point, the 
coast of North Carolina. The fishery was begun on the coast of Massachusetts and 
gradually extended northward. Consequently, at present the lobster is most abundant 
and attains the greatest size in the northerly part of its range, in eastern Maine, and 
in the northern maritime provinces of Canada. 
(2) There is great diversity in the character of the environment which explains 
in some measure the many variations which occur in the habits of the animal, as in 
the time and frequency of molting, in egg-laying, in the hatching of the young, and 
in the rate of growth. 
(3) The lobster displays a considerable degree of intelligence and possesses organs 
to which the various senses of the higher animals have been ascribed. The tactile 
sense is diffused over the whole body, and the dead shell is perforated by innumerable 
minute pores which are capable of transmitting stimuli to sensitive cells lyiug in the 
delicate skin below. It has the sense of smell and of taste, but it is doubtful if the 
so-called auditory organs are really ears. 
(4) The sea-bottom is the natural abode of the lobster in the adult state, and it 
never leaves it and never forsakes the water unless obliged to do so. 
(5) Migrations . — No coastwise migrations are known to occur, but large numbers 
of lobsters move to and from deep water in fall and spring. This bathic migration 
varies in accordance with the character of the coast and nature of the bottom. It is 
influenced by the temperature of the ocean, by the abundance of food, and to some 
extent by the molting and breeding habits. 
(6) Many lobsters remain in the relatively shallow and cold waters of harbors 
throughout the winter, but at this season they are found only upon rocly bottoms, 
where food is most abundant. One may search for them in other situations, as on a 
weedy or muddy bottom, during the winter season in vain. 
(7) Influence of temperature . — The optimum temperature of the lobster is about 
55° F. When the temperature of the sea marks 50° to 55° in spring (May at Woods 
Hole) large numbers of lobsters begin to creep nearer the shores, and when again in 
the fall (October at Woods Hole) the temperature is near this point, they have already 
begun the outward movement. 
(8) In severe winters lobsters are either driven into deeper water or, if living in 
harbors, seek protection by burrowing in the mud when this is available. This some- 
times happens when a sudden lowering of the temperature arises from any cause, and 
always when the animals are confined in pounds. In such cases a prolonged cold spell 
may prove fatal (see p. 26). The lobster is practically excluded from the coast of 
Labrador east of the Straits of Belle Isle by the Arctic current and lingering ice. 
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