NATURAL HISTORY OF AMERICAN LOBSTER. 
351 
any conditions. Since the young feed upon moving or suspended prey, their life can not 
be spent far from the surface. Their behavior at any given time is the resultant of all 
the conditions which affect them at that time, and therefore varies with the varying 
conditions of their life. The rarity of the larval lobsters at the surface in areas where 
the adults are known to abound may be ascribed to the following causes: (1) Wholesale 
destruction of the breeding animals, which has caused the present depletion of the 
fishery; (2) the great destruction of the young, which must take place under natural con- 
ditions; (3) the wide dispersal of the young by tides and currents which their swimming 
habits favor, and (4) the variable character in their reactions or movements, leading to 
a variable or irregular vertical distribution. 
(4) The food of the larval lobster consists of minute pelagic or floating organisms, 
such as copepods, crustacean larva:, algae, and probably to some extent protozoa. The 
stomachs of young lobsters taken at sea have been found to contain fragments of crus- 
taceans, diatoms, algae, fine sand grains, and amorphous matter. They seem ready to 
attack and seize any small moving object, living or dead, which they are able to master. 
Since they follow moving objects like copepods by sight they discriminate to some extent, 
but their powers in this direction are slight, and would seem to be unnecessary if they early 
acquire the adult habit of regurgitating the indigestible residue of their food. 
(5) The preying instinct, which is closely associated with that of pugnacity, is 
very strong in young lobsters from the time of birth. Their disposition to attack and 
devour one another, as seen in aquaria whenever they are too closely crowded or not 
supplied with the proper food, is the obvious result of an indiscriminate instinct to 
seize floating objects which are neither too large nor too active. Another lobster is as 
good a mark as a floating egg, or as a swimming copepod, which is more apt to elude 
them. Indeed they often give chase to crustaceans larger than themselves. The fight- 
ing instinct, if we may thus describe the tendency referred to, is closely associated with 
the primary instinct to seize and devour, in accordance with which the character of 
their activities and the structure of their bodies is distinctly correlated. It is thus 
evident that the organic food of the young lobster must be finely divided and floating, 
and that crowding in too close quarters can not be otherwise than destructive. 
(6) The body of the larva is covered with a cuticle, which includes the lining of the 
stomach sac, and at least a part of the intestine. This is continuous with every spine, 
seta, or hair with which the body is protected or garnished, as well as with the internal 
skeleton which is produced from folds or pockets of the skin. Active growth entails 
the shedding of this cuticle, which is cast off in one piece, and the duration of the molting 
intervals or stage periods depends on the vigor and health of the individual. Each 
molt is a crisis in the animal’s life. If the cuticle is not properly shed, the swimming 
hairs can not be properly evaginated, and the animal becomes helpless. 
A healthy larva is always clean and transparent, while in a weakened or sickly 
one the hairs tend to gather sediment and parasites. Sea water of normal density in 
which the plankton or floating population of animal and plant life is properly balanced 
and an undue amount of sediment is not present, are important conditions for rearing 
the young, and the warmer the water, within certain limits, the more rapid the growth. 
