PIKES AND PIKE PERCH 17 
diluted. The chance of a normal ripe egg remaining unfertilized 
therefore must be extremely small. Their studies further tend to 
show that failure of the eggs to segment is not necessarily related 
to lack of impregnation. They hold that it is impossible, even after 
8 hours, to designate eggs as unfertilized when the absence of seg- 
mentation is taken as a criterion. The conclusions reached by these 
investigators may be summarized as follows: 
The generally accepted theory that the high death rate in pike- 
perch eggs is due to lack of impregnation is unwarranted. ‘The 
present methods of preventing cohesion of the eggs are responsible 
for a portion, but not all, of the losses. Approximately 50 per cent 
of the losses that occur in the eggs during incubation are due to 
ihe same agency that manifests itself in abnormal development. 
The cause in all probability is to be found in the practice of retaining 
adult fish in artificial inclosures for the development of eggs and 
sperm. 
TRANSPORTATION 
Shipment of pike-perch eggs a great distance can not be made 
successfully owing to the short incubation period. For short-dis- 
tance shipments, as from a field or collecting station to the main 
station, the eggs ordinarily are carried in kegs or cans of water. 
Where long distances are involved, the conventional shipping case 
or some modification of it is used, the eggs being spread in thin 
layers on trays, which are then stacked in a suitable container. The 
fundamental advantage of the case is that it gives sufficient insula- 
tion to maintain the eggs at an even temperature throughout the 
journey and protects them from any severe shock or concussion. 
The egg trays in general use are 14 inches square inside and are 
constructed of material three-fourths inch thick by seven-eighths 
inch wide, the bottoms being covered with lnen scrim or heavy 
cheesecloth. The egg cases are constructed of 34-inch pine lum- 
ber and are built large enough to accommodate the tray and an 
inner compartment, in which the trays are placed. This inner com- 
partment has a 2-inch space between it and the outer case, which is 
filled with ground cork or other suitable insulating material. An air 
space of one-half inch is provided between the stack of trays and the 
inner compartment, also, the trays being held in place by means 
of a 14-inch strip nailed in the middle of all four sides of the 
compartment. 
In packing a shipment of eggs the trays are thoroughly soaked in 
cold water. The proper amount of eggs is then measured upon each 
tray, these having previously been covered with mosquito bar several 
inches wider than their outside dimensions. The eggs are carefully 
distributed over the surface of the tray, and the mosquito bar is 
brought in and lapped over the top of the eggs. Unless the ship- 
ments is to be in transit for a day or more it is not necessary to use 
moss. When moss is used it is placed between the eggs and the 
wooden frame of the tray, and frequently some of it is scattered 
over the top of the eggs, the mosquito bar preventing it from com- 
ing in direct contact with the eggs. The best moss for this purpose 
is known as sphagnum. It is well soaked in water before placing it 
