156 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



of the eggs from the parent fish and the absorption of the yolk sac. 

 Eggs, when transported, were x^laced on trays and put under melting 

 ice, and later experiments have been conducted inside refrigerator 

 boxes. Pathological changes or deformities are induced in the embryos 

 when subjected to too low a temperature or when held long enough on 

 damp flannel trays (ordinary air temperatures) to hatch. 



It would appear that 55° to 53° is the lowest temperature in which 

 ova will safely undergo their normal develojjment and 9 days is the 

 longest i)eriod of incubation attainable at that temperature — time suffi- 

 cient, when added to the several days required for the young to absorb 

 the yolk-sac, to ship them to Europe, which has so far failed. One 

 drawback is the rapid development of fungus, which grows over the 

 eggs, penetrates the membranes, and kills the ova. 



Retardation of the hatching of shad eggs has not been turned to 

 practical account, but eggs can be transported hundreds of miles on 

 trays, large numbers beiiig moved at a relatively small expense com- 

 pared with the same number of fry. 



Eggs from the Potomac River are sent to Washington, a distance of 

 12 miles, by steamer, and nearly a mile over cobblestone streets in 

 Washington. Formerly they were put on the trays soon after being- 

 taken, but in April, with night air-temi^erature as low as 49°, and in 

 June, with the relatively high temperature, the quality was bad ; they 

 did well between 00° and 05°, and later they were put into hatching- 

 vessels and kept in motion 12 hours, when they became hard, and went 

 forward in better condition. Since 1888 they have been retained in 

 hatching-jars for 30 hours preceding transfer. 



They are shipped in crates of 20 shallow trays, the frames of the 

 latter being of wood with bottoms of wire mesh about 8 to the linear 

 inch. Wood and wire are painted with asphaltum. Each tray is 

 covered with cheese-cloth, somewhat overlapping the edges, the cloths 

 being hemmed, to avoid ravelings. There are two frames of wood, 

 connected with leather straps; one the base and the other the cover for 

 the stack of trays. The trays, after being filled with eggs, are wrapped 

 in a long, cotton-goods apron and strapped together. There is an iron 

 handle on the top frame, and the lowermost tray is put down empty 

 with the wire surface upward. Then follow the trays containing eggs, 

 the uppermost one being put on empty with the wire surface up. The 

 top and bottom trays are merely to protect the others. 



The greater part of the water above the eggs is poured off from the 

 jars and the remainder poured into tin jians along with the eggs. 

 The cloths, after soaking in water, are arranged one by one on the 

 trays and tucked closely into the four corners. The trays are stacked 

 up and eggs poured evenly over the surface of the top one with a 

 large dipper, and each tray, when filled, is put on the crate base. The 

 surplus water drains away to the manipulating table. Tray cloths of 

 material too closely woven to let the water through are unsuitable. 

 The eggs are bailed up in dippers with the water that they are in, and 



