22 BULLETIN OF THE UNITED STATES FISH COMJIISSION. 



limited to a period of about two montlis, it is probable that the eggs of 

 many individuals reach maturity at about the same time, and a large 

 number of jars can be manipulated together. 



The principal object in hatching the eggs in jars is to have the em- 

 bryos under control immediately after hatching ; but the best methods 

 of caring for the young have yet to be decided upon, and furnish an in- 

 teresting problem for investigation next spring. It is probable that the 

 embryos cannot be kept in the McDonald jar, as they swim at the sur- 

 face and would soon all escape through the outlet tube. They can, 

 however, be transferred to large aquaria, to the large wooden tanks now 

 rigged on the lower floor for the keeping of fish, or to floating cars in 

 one of the basins. The last plan will probably answer best when work- 

 ing on a large scale, as the embryos will thereby obtain some food from 

 the surrounding waters, while iu both of the former cases food would 

 have to be supplied them. 



A floating car suitable for the purpose has already been constructed, 

 and now contains a number of berried lobsters, which it is proposed to 

 keep over winter, if possible, in order to observe whether any hatching 

 takes place during that season. This car is constructed on the plan of 

 the ordinary fish cars, the opeuiugs being covered with a fine-mesh 

 brass-wire cloth to prevent the escape of the young, but with the 

 meshes large enough to permit of the entrance of such small life as the 

 embryos would be likely to feed upon at the surface. The dimensions 

 of this car are 5 feet long, 3 feet wide, and 2 feet deep, but larger cars 

 will be used if necessary. It is now moored in the outer basin, oj^posite 

 one of the openings in the wall, where it receives the full force of the 

 current. A few McDonald jars will also be kept in operation, with lob- 

 ster eggs, during the entire winter, for purposes of observation. 



It is not known how long the young can be kept in confinement, nor 

 at what age it would be advisable to turn them over to the care of 

 nature, but it will probably be possible to transport them alive to any 

 other portion of the eastern coast, as the distances are nowhere great. 



Note. — Since the above was written, a letter has been received from 

 Capt. H. C. Chester, superintendent of the Wood's IIoll station, giving 

 an account of the hatching of a few lobster eggs in one of the McDonald 

 jars early in November. The eggs were detached from the lobster and 

 l^laced in the jar November 5 ; they began to hatch November 8, three 

 days afterwards, and continued hatching for a few days longer, but 

 only about 50 young ones were observed. The remainder of the eggs 

 are still in the jar, iu good condition. A few of the embryos were 

 transferred to an aquarium with running water, and others to a small 

 vessel in which there was no change of water. The former lived about 

 20 hours, the latter about 36 hours. The temperature of the water in 

 the hatching-jar November 5 was 54.3° Fahrenheit; on the Cth, 55°; 

 and on the 7th and 8th, 50°. 



