INTRODUCTION. 13 



more than doubled its former length, the mouth, 

 gills and abdominal viscera are visible, and it 

 manifests a desire to take food, by nibbling at 

 the unhatched eggs, and pieces of meat placed 

 in the vessel containing them. Its color is now 

 materially changed, being of darkish gray on its 

 back and upper portions of its side. The sack 

 suspended from the abdomen at this time be- 

 comes smaller, and less globular in form, being 

 more contracted anteriorly than posteriorly. The 

 habits of the little creature are also much 

 changed, as it now swims smartly, and endeav- 

 ors to hide itself when disturbed. 



Owing to imperfections in our arrangements 

 where we placed the eggs for hatching, accumu- 

 lations of sediment buried them up, destroying 

 them by hundreds; this accumulation was much 

 more fatal when the embryo fish was nearly 

 ready to make its exit from the egg. To avoid 

 their further destruction, on the 26th of January 

 we brought the remaining eggs to our office, 

 and placed them in a glass jar, and supplied 

 them, and the young fish, daily with fresh water. 

 In this situation they have remained until the 

 present time, the young fish making their ap- 

 pearance from day to day, the last one ruptur- 

 ing its oval envelope on the 10th day of Feb- 

 ruary. I have seen as many as six make their 



