THE EGG AND DEVELOPMENT OF THE CONGER EEL. 
41 
parent spheres not unlike those of the eggs of certain clupeoids. There are present, 
from one to six light-yellow oil-spheres of variable size. If more than one are present, 
then one is always much larger than any of the others. The yolk measures 1.75 to 2 
mm. Some of the young were found to be hatched on the morning of August 3. 
d' 
Fig. 4. — Embryo freed from its membrane, showing continued constriction of anterior end 
of yolk and general diminution of the enlarged anterior portion of yolk with the corre- 
sponding increase of caudal portion of yolk. August 2, 7.30 a. m. 
Since many of these developed gaping jaws and some others, which did not hatch till 
several days later, developed normally, it is possible that the early hatching was 
not normal, Raft'aele’s eggs hatched in five or six days. He was able to keep them 
four or five days after hatching. For some time after hatching the larvae floated 
with their heads upward — the probable 
result of the location of the oil-spheres. 
On August 6 they had assumed a normal 
horizontal position and the characteristic 
eel-like progression, but the pectorals 
were not yet used in swimming. Later 
they were seen eeling their way through 
the water, not infrequently nosing about 
the bottom and voraciously seizing any- 
thing that came in their wa} f . 
The characteristic feature of the 
eggs at the time I began to observe them. 
August 1, was the shape of the yolk. 
The bulk of this occupied the usual posi- 
tion, but a narrow stalk extended back 
below the alimentary canal. The oil- 
sphere or spheres occupied the extreme 
anterior part of the yolk 1 (figs. 1 and 2). 
The further history of the yolk in this 
species is unique among fishes and not 
sufficiently emphasized by Raffaele. In 
fig. 3 it is seen that the yolk is no longer rounded anteriorly, but that it ends j n a 
marked protuberance and that the oil-sphere lies in this. The general mass of the 
yolk still retains the original shape and distribution. The anterior protuberance 
now becomes longer and at the same time narrower, so that the oil-sphere loses its 
rotundity and becomes elongate (fig. 4). At the same time the general mass of the 
Fig. 5. — An embryo, of the same stage as Fig. 4, in its mem- 
brane, from below. 
1 All drawings were made from living specimens, or such as had just been killed by formalin, 
alimentary canal; fv, fourth ventricle; ylk, yolk; l, liver; h, heart; o, oil-spheres. 
In the drawings, al, 
