120 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



the car near the bottom and are made to revolve slowly — about nine 

 revolutions per minute. The motive power for the propeller is 

 furnished by a gasoline engine situated in one of the houses and con- 

 nected with the propeller shaft by a system of steel shafting and 

 mitered gears (fig. 3) . Each propeller can be thrown in and out of 

 gear independently. 



HATCHING METHODS. 



Handling the egg lobsters. — The method now used in hatching the 

 eggs is simple. The old female lobsters carrying eggs (fig. 9) about 

 ready to hatch are put directly into boxes and the paddles are set 

 in motion. As the old lobsters crawl about on the bottom of the cars, 

 the eggs hatch out one by one and the larvae, caught immediately by 

 the upward revolving current, are carried up and off the bottom as 

 they are in the ocean. Twenty or 30, or even 50 or 100, lobsters may 

 be put in one car. When the number of old lobsters is large, we have 

 found it well to replace the long propeller by a shorter one hung some- 

 what farther from the bottom so that the old lobsters will move freely 

 over the bottom with tail extended and not crowd up into the corners. 

 Screens, placed over the top of the box, thereby shading them from 

 the strong light, also help to prevent crowding (fig. 7). As soon as a 

 sufficient number of fry have hatched out the old lobsters are removed 

 to another car to repeat the operation. The length of time required 

 to hatch out a full complement of fry in one box varies, of course, ac- 

 cording to the various conditions; that is, the number of egg lobsters, 

 the condition of the eggs, the temperature of the water, etc. 



Precaution as to age of fry. — It is of great practical importance to 

 have a full complement of fry hatch out as quickly as possible — with- 

 in at least one day-^so that all will be about the same age. Otherwise 

 when the fry moult, the older individuals, having passed through the 

 moult and recovered their strength and appetites, are very destructive 

 to the small or freshly moulted larvae. The effects of this discrepancy 

 in the ages among lobsters of one batch are especially injurious when 



