350 
BULIvETIN of the bureau of fisheries. 
Woods Hole, of which the four most common species were Licmophora tincta, Diatoma 
hyalinum, Rhabdonema arcuatum, and Tabellaria unipunctata, named in the order of their 
relative abundance. 
I have seen the fry almost buried out of sight by diatoms in neglected jars at Woods 
Hole, especially by Tabellaria, which at times was very abundant and destructive. 
Other organisms found by Gorham to infest the young lobsters at Woods Hole were 
a filamentous green alga and a stalked protozoan, Ephelota coronata, which was more 
abundant in the waters of Wickford, R. I. 
Cannibalism may be reduced by supplying the young with proper food, by agitating 
the water and thereby keeping both the young and their food suspended, and by avoiding 
overcrowding. The growth of diatoms can be checked or prevented, according to 
Gorham, by filtering the water; by selecting a suitable station for the rearing apparatus 
where diatoms do not abound, and where the temperature is high or most favorable for 
hastening growth and molting, by which the little animal escapes for the time being at 
least from all its troublesome messmates; by frequent cleaning, coating, or renewal of the 
rearing bags; and by reducing the light and thus hampering the diatoms by cutting down 
their food supply. (Compare, p. 281.) 
THE SIGNIFICANT FACTS OF LARVAL AND LATER DEVELOPMENT. 
Some of the most important facts concerning the larval life of the lobster may now 
be summarized: 
(1) The young are hatched in great numbers, 5,000 to 100,000 eggs or young being 
produced at one time by a single animal according to its size, the number increasing 
rapidly in proportion to the cube of the body length or to the total volume of the body. 
This leads us to expect great destruction of the young in nature, an expectation which is 
unfortunately realized. It is a vulgar error to assume that the abundance of this ani- 
mal or of any other species is proportional to the number of young born, since it neglects 
the equally important question of the destruction of the young or their rate of survival. 
The rapid rise in production beyond the lo-inch size proves that the older the animal the 
more valuable it becomes for reproductive purposes, barring the question of sexual 
decline, which is of little importance in an animal so seldom permitted to grow old. 
(2) The larvae are hatched at the bottom of the ocean in relatively shallow water at 
night or in early morning. A molt occurs at the time of hatching; parental instinct 
ceases; the larvae are soon dispersed, and leaving the bottom lead a free-swimming, 
pelagic existence for a period of from 3 to 6 weeks (see p. 348), according to circumstances. 
Summer eggs on the coast of Massachusetts are hatched from May 15 to July 15, the 
majority being extruded in June. 
(3) The movements of the larvae in a natural state are not fully understood. Under 
certain conditions they rise toward the stronger light at the surface; under other condi- 
tions they retreat from the light, sinking to greater depths. They have been taken near 
the surface in the townet in both strong sunlight and at night, both with and without 
the aid of artificial light. At the present time they are seldom found at the surface under 
