272 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
adhesive material with which the eggs are covered seems to be dissolved somewhat 
and becomes diffused through the water, so that the whole becomes ropy. If a lot of 
the eggs is takeu up in the hand from the water glairy filaments formed of the ropy 
solution will trickle down between the fingers, and if the wind is blowing these may 
be drawn out for the length of 2 feet or more. 
This glairy or ropy character of the partly dissolved coating of the eggs persists 
for some time, usually for thirty minutes or so, after which time the glairy substance 
hardens or coagulates in the presence of the water and the gases held in solution by it. 
In process of hardening the glairy, sticky coating of the eggs firmly fastens them to 
whatever they are brought into contact with, and after that has occurred it is scarcely 
possible to detach them without injury to their delicate, thin envelops and their soft, 
viscid contents, consisting of yolk substance and protoplasm. The sticky coating of 
the eggs finally remains as a grayish-white, tough, slightly elastic covering envelop- 
ing the egg membrane proper, and varies in thickness at different points on the surface 
of the ova. It is also the material which will cause the eggs to adhere in clusters or 
masses, sometimes as large as a man’s head, if they are left together in large quan- ' 
titles in a vessel with a little water. 
The trays used at Delaware City, on board the steamer Fish Hawh, were made by ! 
tacking cheese-cloth to light wooden frames a foot wide and 18 inches long, then 
loading the edges of the frames with strips of sheet lead to keep them immersed. 
These trays placed on ledges in a superimposed series, in a trough through which 
the water is allowed to flow gently, is a very efficient hatching device. Floating 
hatching boxes with brass wire gauze bottoms and small openings at the sides 
covered with the same kind of gauze have been successfully used by the (Germans, one 
having been brought from Germany by Mr. S. Feddersen, of Port Penn, Del., from 
Hamburg. This device is quite simple and was placed at my disposal through the 
courtesy of Mr. E. Anderson, of Delaware City. It seems to me very well adapted for 
the purpose for which it is designed. 
The floating box in which the writer succeeded in hatching out a batch of the eggs of 
the sturgeon was exceedingly simple in construction and consisted of a soap box with 
the top and bottom removed, the bottom for which was then replaced by tacking cheese- 
cloth to the lower edge of the rim, and by nailing wooden strips to serve as floats to 
the sides of the box, a very efiflcieut hatching device was extemporized. These boxes 
so modified were placed at the edge of the large fresh- water pool near the extreme 
eastern end of the Chesapeake and Delaware Canal at a point where there was a con- 
stant flow of fresh water under them. The only lot of fertilized eggs which the writer 
succeeded in obtaining were spread on the bottoms of these boxes .and left to hatch. 
In six days from the time of fertilization the young fish made their apiiearance. , 
The rapid appearance of a parasitic fresh water fungus, however, caused such exten- 
sive mortality amongst the eggs that very few embryos survived to escape from the 
egg membranes. This fungus, which appeared to be a Saprolegnia, is developed from 
spores which seem to be almost everywhere present in fresh water. The mycelium 
spreads very rapidly, attacking dead eggs first, and spreading from them to the live 
ones, which are then invaded and killed or asphyxiated by the fungus. The only way 
in which this pest can be kept down is to go over the trays and with a small forceps 
pick off the dead eggs and keep the living ones as clean as possible. Where the 
work of propagation was being conducted upon a large scale the attendants would 
