1915] ON CLureEA PALLASIZ CUVIER AND VALENCIENNES 107 
on itself, but passes back from near the symphysis of the lower jaw 
without showing an appreciable difference in size in its various parts. 
After the embryo has hatched ouc there is enough yolk remaining 
to last it about six days. During this time the principal changes that 
take place have to do with the digestion and the circulation, since a 
preparation must be made for active feeding instead of living by ab- 
sorption of food material from the yolk. The nervous system has not 
changed a great deal, although the pineal body is now evident. The 
nasal pits are relatively larger than in the younger specimens. The 
heart is now doubled over and shows more of a difference in the chambers. 
The cartilaginous skeleton has begun to develop. The basis cranti 
appears as a united plate forward, but farther back it separates, appear- 
ing on both sides of the pituitary body, back of which it is again united 
below the anterior end of the notochord. Lateral projections grow up 
from this base so that for a little distance the notochord is almost sur- 
rounded by cartilage. At the posterior end it supports the palato- 
quadrate cartilage, which is well developed, as is also Meckel’s cartilage 
in the lower jaw. Each of the gill arches is supported by a cartilaginous 
rod. Except at the anterior end there is no indication of the skeletal 
structure appearing to encroach on the notochord; scarcely any change 
is noticeable in it from the time of hatching. The only other skeletal 
\portion appearing is in the pectoral girdle, where there is a well developed 
cartilage on each side, but these do not come very near together in the 
middle line. ‘There is as yet no indication of a pelvic girdle or pelvic fins. 
The mouth now opens to the full width and the lower jaw articulates 
freely. In the digestive tract there is now a distinct enlargement for 
the stomach, the walls of which are already glandular. The intestine is 
of uniform appearance and passes as a straight tube to the anal opening. 
The liver shows the greatest development of any of the organs, as now 
it has become a solid mass of relatively large size, showing already a 
division into lobes. I have not been able to make out any sign of a pan- 
creas, although in other fish—the blue cod, Ophiodon elongatus, for 
example—it becomes quite definitely established some time before the 
yolk is all absorbed or even before the embryo is hatched out. The 
kidney and its ducts show little change. 
From the time the yolk is absorbed it has not been possible yet to 
follow continuously the process of growth. After a couple of weeks 
there is a gap until the fish is about 63 months old on Oct. 9th. By 
this time the average length is about 5.2 cm. and the weight 1.5 grams. 
The scales are already well started. On Feb. 16th they have reached a 
length of 6.3 cm., April 4th, 6.5 to 7.0 cm. and on May 16th (14 months), 
Fath Ch. 
