A METHOD OF LOBSTER CULTURE. 229 
Another most important function of the current is the holding in suspension 
of solid particles of food, so that they come within easy reach of the larve. 
Incidentally, also, it increases the supply and availability of pelagic living 
food, for the latter is drawn into the car through the bottom and kept alive by 
normal conditions of the water. An adequate supply of available food is per- 
haps the most efficacious preventive of cannibalism. 
The maintenance of normal conditions of water in a car is also accom- 
plished by this method. The temperature and density of course vary little 
from that of the surrounding water. The water is constantly renewed either 
through the porous sides or, in the case of wooden cars, through screen windows 
in the bottom, egress being allowed for by screens in the sides. Since the cur- 
rent is internal and mainly tangential to the sides of the car, the fry are not 
carried violently against the ex-current screens, as in the case of a tidal current 
passing in one side and out the other. There is not much need of rapid renewal 
of water, however, because the water is continuously brought to the surface by 
the upward trend of the current, where by exposure to the air it is recuperated 
with oxygen and relieved of waste gases due to the metabolism of contained 
animals or the decomposition of unused food. 
In a word, it may be said that by this method the pelagic lobster fry may 
be kept in confinement and under observation in inclosures of natural water, 
protected from their usual predatory enemies, maintained in natural pelagic 
condition by being prevented from going to the bottom, provided with either 
living or artificial food held in suspension, and that the tendency to cannibalism, 
always evinced when the fry are confined, can be considerably mitigated. 
APPARATUS. 
The particular form of apparatus by means of which this method has been 
successfully applied to the rearing of lobster fry during the last few years at 
Wickford is in some respects a special adaptation to the establishment in connec- 
tion with which it has been evolved, and certain details of construction are ves- 
tiges of former experiments too good to be cast aside, but not to be exactly copied 
in new construction. As it stands to-day, the apparatus consists of a house- 
boat built like a catamaran of two pontoons, with a “well” or open space 
between them, originally intended and used, indeed, for holding experimental 
cars. At both ends the space between the pontoons is decked and on each deck 
is a small house. The houseboat floats on the water, moored securely in a 
small cove directly over the channel in a good tideway (fig. 1, pl. vm). It forms 
the nucleus of a collection of skeleton rafts which nearly surround it and which 
all together occupy a considerably larger area than the houseboat itself. Four 
rafts, 19 by 75% feet, lying two on either side of the houseboat, contain the cars 
for hatching and rearing lobster larve. The rafts of each pair are bolted fast 
together and buoyed by barrels (fig. 1). The inside rafts on either side of 
