118 EEPORT OF COMMISSIONERS OF INLAND FISHERIES. 



important function of the current is the holding in suspension of soHd 

 particles of food, so that they come within easy reach of the larvae. 

 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, perhaps, the most efficacious preventive 

 of cannibalism. 



The maintenance of normal conditions of water in a car is also ac- 

 complished by this method. The temperature and density, of course, 

 vary little from that of the surrounding water. The water is con- 

 stantly 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 current is internal and 

 mainly tangential to the sides of the car, the fry are not carried vio- 

 lently 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 decom- 

 position 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, main- 

 tained in natural pelagic condition by being prevented from going to 

 the bottom, provided with either living or artificial food held in sus- 

 pension, 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 



