26 XT. S. BUEEAU OF FISHERIES. 



method involves the use of a case of suitable size, with the usual pro- 

 vision for insulation and ice-hopper. The trays are divided into 

 compartments or pockets 2 to 4 inches deep into which the eggs, 

 wrapped in cheesecloth or mosquito bar, are placed. The dimen- 

 sions of this type of case used at the Leadville (Colo.) station are 

 15^ by 22 by 13f inches deep, outside measure. Each case contains 

 four trays 8^ by 19^ inches and 2| inches deep. These are divided 

 by cross partitions into three pockets 6 by 7f inches, with an ice 

 hopper 11 by 19^ inches and 2^ inches deep. Such a case will 

 carry from 100,005 to 150,000 eggs. 



The superintendent of the Springville (Utah) station has de- 

 scribed a method of packing the green eggs as follows : 



In putting the eggs on the hatching trays at the field station a 2-quart dip- 

 per is tilled with water and over it is laid a piece of mosquito netting or cheese- 

 cloth about IS inches square. Into this a measured lot of eggs— enough to fill 

 one pocket in the shipping tray, between 20 and 30 ounces — is poured. The 

 cloth is then lifted by the four corners and deposited, with the eggs, on the 

 hatching tray. Here they remain until the time for shipment arrives. In ship- 

 ping, wet moss is first placed on the bottom of each pocket, the shipping tray 

 is submerged in water, and the eggs are lifted from the hatching tray as de- 

 scribed and deposited thereon, a light layer of moss being placed on top. If 

 desirable, the eggs may be shipped as soon as " water hardening " is completed. 



INCUBATION OF THE EGGS. 



Wlien eggs are received from a collecting station or other source, 

 their temperature is compared with that of the water in the hatch- 

 ery, and before installing them in the troughs any wide difi'erence 

 is equalized by slowly adding and pouring off the hatchery water 

 in small amounts. A quantity of the eggs, sufficient to register at 

 the 32-ounce mark, is poured into a graduate full of water. The 

 eggs are settled together by shaking the graduate, and enough are 

 added to make up the deficiency thus caused. One such measure 

 is placed on each tray, and any remainder is put into another iray 

 to comprise a broken lot. As soon as it is convenient to count 32 

 fluid ounces of the eggs and ascertain the number contained in each 

 tray, those in the broken lot are drawn upon and counted into the 

 separate trays until the count of each is the even number decided 

 upon for a tray unit. Owing to variation in the size of the eggs 

 this may be any number from 10,000 to 15,000. 



The incubation of the eggs beyond the eyed stage does not differ 

 materially from the eying process. While the equipment at dif- 

 ferent stations varies somewhat to meet local conditions, the general 

 l^rinciples of the work are the same. From this time on the care 

 of the eggs consists in removing the dead ones and keeping the good 

 ones free of silt, which is dislodged by raising the tray slightly and 

 settling it back into place. In the event that the eggs become very 

 dirty they may be removed from the trays or baskets, cleaned as 

 described on page 24, and then returned to the traj^s. The fry are 

 hatched in the troughs in which the eggs are incubated and are 

 retained there until ready for distribution. The original number 

 of eggs in each receptacle is maintained by the systematic daily 

 addition of eggs from the broken lots to make up for any losses that 

 may occur. 



