STRUCTURE AND DEVELOPMENTAL RATE 131 



When 19 days old the control were almost all hatched actively free 

 swimming young fish. The. few yet imhatched seemed normal and 

 ready to hatch at any time. 



Lot Ci contained a majority hatched and all seemed normal. 



In lot Co there were not quite as many hatched, but all were in 

 good condition. 



Lot C3 were about the same in hatching record, so there was little 

 effect to be noticed at this time resulting from the two days spent in 

 the refrigerator following their first 23 hours of development. 



Lot C4 had remained longer in the refrigerator, 4 days, and at this 

 time none had hatched, though they seemed fully ready. In lot C5 

 also none had hatched. 



Lot Di contained a majority hatched, almost as large a proportion 

 as the control. These had remained in the cold only two days. Lots 

 D2 and D3 had remained in cold for 4 days, and only one specimen in 

 the two groups had hatched. All appear normal and ready to hatch. 



When 20 days old, the first one in C4 had hatched. In lots D2 and 

 D3 many had now hatched, so these are not very much later than the 

 control in spite of their 4 days' arrest. 



In lot C5 none had yet hatched, although during the next 24 hours 

 many of them did hatch. 



When 22 days old, a few of the control were still unhatched, though 

 they were normal. Lot Ci had 12 unhatched and 50 hatched. Lot 

 C2 contained 18 unhatched and about 80 hatched. I^ot C3 had 29 un- 

 hatched, one with a deformed body, and about 70 normal ones hatched. 

 This record was about as good as a usual control. 



About half of the C4 lot had hatched, and all seemed normal, though 

 they remained in the refrigerator twice as long as Ci, C2, and C3 had. 



Lot Co also showed about half of the specimens hatched. 



Lot Di had 7 unhatched and about 60 hatched, all of them seemed 

 normal. 



Lot D2 contained 29 unhatched and about 40 hatched, all of which 

 were normal. 



Lot D3 showed 20 unhatched and about 30 hatched. 



When 25 days old, every egg in the control had hatched. 



Lot Ci, only 4 were unhatched, one of these had abnormally small 

 defective eyes and no blood circulation. So these are a little behind 

 their particular control in quality at this stage, but very little, and 

 probably their disadvantage is of no significance, since such a single 

 specimen might occur in any group of eggs. 



Lot C2, every specimen hatched. In lot C3 only 3 failed to hatch. 

 One of these was grossly deformed and the other two had slightly 

 abnormal eyes. So this group is somewhat inferior when compared 

 with the control record. 



Lot C4 contained 12 specimens still unhatched. One hatched speci- 

 men was bent and unable to swim. One of the 12 unhatched was 

 abnormal, so this record also was a little worse than the perfect control. 



