[31 PROPAGATION OF CODFISH. 785 



individuals that mature earliest in the season yield less healthy eggs 

 than those spawning in the height of the season, and we may suppose 

 that the eggs taken iu November were from fish prematurely ripe. The 

 unsatisfactory results from the eggs brought overland must, however, 

 be attributed to th§ conditions under which they were taken and trans- 

 ferred. They were taken frequently under the great difficulties attend- 

 ant on a boisterous sea and extremely cold weather, Lad generally to be 

 kept over night, while awaiting shipment, in jars or other vessels, and 

 their transfer by express involved their confinement for many hours, 

 in a crowded condition, in small jars of water hermetically closed, with 

 at best a scanty allowance of air. I do not think the ill success attend- 

 ing these transfers at all settles the question of the practicability of 

 this method of collection under varied conditions. It might be possible 

 to bring them through in perfect health by more careful attention to 

 the necessity of a constant aeration of the water. This, however, is a 

 matter for future experiment. 



As a rule the fry were liberated as soon as practicable after they 

 were hatched. If, as was commonly the case, the period of hatching 

 out was protracted, those first breaking the shell were taken out of the 

 jars and liberated, while the remainder of the lot were left in the jars 

 to hatch. A single lot of the fry, numbering 2,050,000, was taken by 

 the Grampus, on the 27th day of January, and liberated near Kace 

 Point in Cape Cod Bay. All the others were liberated iu the imme- 

 diate vicinity of Wood's Holl, sometimes on the flood tide, which would 

 carry them into Vineyard Sound, and sometimes on the ebb, which 

 would carry them into Buzzard's Bay. 



The experiment was tried iu several instances of keeping the fry iu 

 aquaria until they should attain some growth. The conditions of these 

 experiments were greatly varied, but no satisfactory result was obtained 

 in any case. Although appearing to be in good health when put into the 

 aquaria, the fry invariably dwindled away until all or nearly all were 

 gone. Egress was so guarded against that there seems little doubt 

 that in most cases the disappearance was the result of death. It seemed 

 impossible to so arrange the screens that the young cod would not be 

 drawn against them and die. Whether the egress of the water was 

 constant or intermittent (which latter condition we obtained by means 

 of a tidal movement), in every case the result was practically the same. 



A determination of the conditions under which cod fry can be reared, 

 even to the age of a few weeks, presents to us, therefore, an unsolved 

 problem. It will be necessary to inquire whether the difficulty does 

 not arise, in part at least, from the crowded condition of the eggs in 

 the hatching jars. These jars are of glass, 9 inches in diameter and 15 

 or 16 inches deep, -and eggs enough are placed in one of them to form 

 a layer at the surface a large fraction of an inch in thickness. When 

 this apparatus is in operation the jar is covered closely with cheese- 

 cloth and placed in the hatching-box in an inverted position, the water, 

 S. Mis, 90 50 



