BULLETIN OF THE UNITED STATES FISH COMMISSION. 189 



the tables were introduced, and the station was equipped with 300 of 

 the jars. Each jar having a capacity of 00,000 to 70,000 shad eggs gave 

 a total hatching capacity to the station of 21,000,000 eggs at one time, 

 or 900,000,000 for the entire shad-hatching season. This was, of course, 

 in excess of any expected production; but in the organization of a shad 

 station it is necessary to provide for the contingency of the great bulk 

 of the eggs coming within an interval of a few days of each other. The 

 form of hatching apparatus used during this season is shown in Fig. 4. 

 The general arrangement of a hatching table for the collection of the 

 young fish as they hatch in appropriate receivers or aquaria is also 

 shown in Fig. 4. The present form of apparatus and the form contem- 

 plated in the first design, but only completed recently, is indicated in 

 Fig. 5. 



Fig. 5.— Arrangement of jars for hatching and collecting, as in use at present. 



In this figure we have shown a pair of jars fitted up, one for the 

 hatching of the eggs, the other for the collection of the young fish. 



The jar consists essentially of a cylindrical glass vessel with hemi- 

 spherical bottom. These are not blown, but pressed, in order to secure 

 perfect regularity of the interior surface, upon which depends to some 



