CARE OF YOUNG IN HATCHING-HOUSE. 101 



tion, driving the water toward its as yet unpro- 

 tected gills. Should the fibers of the byssus be 

 present, they are driven directly into the gills, res- 

 piration is impeded, and the fish dies. A warm 

 hatching-house, dry floor, and bulb syringe, com- 

 bined with a keen eye and patience, are now all 

 necessary. As the fishes increase in size they may 

 be more plainly seen, "but the care and attention 

 njow commenced will be constantly required until 

 the fishes are removed to the pond. 



At the end of the fifth week of life the appear- 

 ance of the fish is as in Fig. 22. The yolk sac is 



FIG. 28. 



still present, though its dimensions have been 

 greatly reduced. The fins may be all plainly seen, 

 and even their rays counted. The gills are entirely 

 covered by the gill-covers, and, in short, the 

 whole appearance is more fishlike than that of the 

 nondescript of Fig. 21. From this period the sac 

 rapidly diminishes, but it is not until from the 

 forty-fifth to the fiftieth day after hatching that it 

 is entirely absorbed, and the fish emerges into the 



