116 Papers from the Department of Marine Biology. 
tional. The regions of large functional eggs and of small functionless 
eggs are marked off by an irregular but well-defined line. Forward 
of this line are found scattered eggs, large and small, destined to 
become mature and oviposited; behind it are closely aggregated large 
masses of small eggs, of whose function I am entirely ignorant. These 
regions and their eggs are very clearly seen in figure 1 of plate 1, an 
external view, and figure 4 of plate 3, an internal view of the same 
ovary. However, as the functional eggs ripen, the pedicels of those 
lying near the line of demarcation greatly lengthen and the eggs pushed 
backward by the growing ones in front become crowded in among the 
smaller eggs in the intermediate section, as may be clearly seen in 
figure 4 of plate 3 and figure 6 of plate 4. 
Thus it is that in spent or immature ovaries the ovigerous and 
oviducal portions of the ovary are about equal in length, while in 
the pregnant organ the developing eggs and the distention brought 
about thereby cause each ovisac to become apparently divided into 
two sections of about equal length—the ovigerous section being in front 
and the oviducal portion behind. These phenomena will be made 
clearer in the section dealing with the changes of size. 
When the ripe eggs break from their follicles they fall into the 
lumen of the ovisac and thence pass into the rugose oviducal section 
and so to the exterior. The follicles are left behind and are very 
prominent in an ovary from which the eggs have recently been 
extruded. This is shown very clearly in figure 5 of plate 3. Shortly 
after the breeding season these emptied follicles entirely disappear, 
are completely resorbed, leaving only the 1 to 5 mm. eggs which will 
develop into those of next season’s laying. Small eggs in small vesicles 
standing on short pedicels are found under and around the pedicels 
of the large eggs; they line the whole of the interior of the ovigerous 
portion of each sac. 
The walls of the ovary are fairly thick (about one-eighth inch) and 
tough in the resting stage, but they are very distensible, and, as the 
huge eggs develop, the walls become as thin and (especially in the ante- 
rior section) as transparent as oiled paper. The walls of the ovary 
are composed of two layers, the inner or germinal layer, from which 
the eggs and their follicles are developed, and the outer or peritoneal 
envelope. In ovaries which have been in weak formalin for 8 or 10 
years, the two layers can be easily separated. 
To bring in the food materials required for building up the large 
number of these giant eggs, a generous blood supply must be provided. 
The ovarian artery descends from the hinder region of the kidneys about 
the level of the posterior third of the ovary, but before reaching this 
organ it divides, one branch going forward to the egg-forming section, 
the other backward to the oviducal portion. There seems to be some 
sort of mechanism to send the major portion of the blood to that part 
