
288 MONSTROSITIES AMONG TROUT. 
warmth, for its due flames fill the room with a cheerful 
Pote ... . How glorious is sleep after a day 
of toil; of toil, a still of pleasure. How gently it de- 
scends upon us, how quietly we yield to its embrace; it 
touches the drowsy eye, and we feel that 
“The day is done, and the darkness 
Falls from the wing of night.” 


MONSTROSITIES AMONG TROUT. 
BY A. COOLIDGE, M. D. 
THE egg of a fish consists of an enveloping membrane 
containing the yolk or vitellus. The first step in the devel- 
opment of the egg is the formation of innumerable cells on 
the surface of iie: vitellus, which are closely packed together, 
and form a new membrane or layer surrounding the vitellus. 
The next sign of organization is the Mitkenir and conden- 
sation of one spot of this new layer. The thickened part 
has an elongated oval shape, and in its centre, running longi- 
tudinally, is a delicate line or furrow. 
This is the first beginning of the fish. The backbone of 
the fish is formed around this furrow. The anterior extrem- 
ity spreads to become the cavity of the brain, and the tail 
grows from the posterior end. The yolk remains enclosed 
. in the new layer as in a sac; as the fish grows this sac be- 
. comes constricted, so that the upper part of it is taken up 
-into the body of the fish, while the lower part remains hang- 
ferons. and is called the umbilical vesicle, and it is in Hie. 









he umbilical vesicle, which being too heavy 
: nove, he remains anchored by it, as it were, at 
he bottom of the stream, wriggling only his head and tail. 
le is fed by the | — of the contents of the vesi- 






