No. 393.] AUTODAX LUGUBRIS HALLOW. JOI 
unable to determine with certainty, though what evidence we 
have obtained points to the conclusion that they are of this 
type. We have been unable to find any trace of either nuclei 
or other protoplasmic material, or cell boundaries, in the sec- 
tions of the yolk which we 
have made. But, of course,- 
earlier stages of development 
will have to be studied before 
the point can be definitely 
settled. 
The entire surface of the 
yolk is covered by a very deli- 
cate epithelium which carries 
the vitelline vessels and cap- 
illaries. No pigment is present 
excepting in the embryo itself. 
The general character of the vitelline vessels is shown in 
Figs. 5 and 6. The vitelline arteries, v.a., are given off from 
the dorsal aorta in pairs, there being approximately a pair for 
each myotome of the abdominal region of the embryo. In all 
there are twelve or more pairs. The vitelline veins collect into 
a single large trunk (Fig. 5), v.v., situated on the anterior side 
of the yolk-sac, and corresponding about to the sagittal plane of 
the embryo. The two 
trunks seen in the figure 
at the point of disappear- 
ance behind the head be- 
come confluent before 
actually entering the body. 
(2) The Gills. — These 
are of great size. They 
are three-lobed, the lobes 
being thin and delicate, 
much expanded, highly 
vascular, and widely confluent at their bases. The gills are so 
placed that their dorsal surfaces are close to, and concentric 
with, the inner surface of the egg capsule (Figs. 5 and 6). As 
they are functional during the intra-capsular life of the embryo 
Fic. 5. 
Fic. 6. 
