46 
MR. E. RAY LANKESTER ON THE 
Explanation of Plates 11 & 12 (illustrating Loligo). 
Figs. 1 to 11 are drawn to the same scale. 
Fig. 1. One of the smallest eggs from the ovary of Sepia officinalis at the breeding- 
season (April), inch diameter. 
Fig. 2. A somewhat larger egg. 
gv. Germinal vesicle and spot. 
oc. First appearance of the egg-capsule. 
Fig. 3. An egg further advanced. 
oc. Egg-capsule. 
bv. Blood-vessel. 
Fig. 4. An egg still further advanced (same stage as fig. 18). The yelk has now 
received considerable addition to its substance, and there can be distin- 
guished : — 
oc. The outer egg-capsule. 
ic. The inner egg-capsule, consisting of columnar cells. 
gv. Germinal vesicle. 
Fig. 5. The egg now shows traces of the development of folds or plicse in its capsule. 
Fig. 6. The folds are more clearly developed, and are seen here as focused in a. surface- 
view of the egg. Their connexion with the blood-vessel (bv) is obvious. 
Fig. 7. An egg, further advanced, in transverse section, to show the disposition of the 
now greatly enlarged folds of the inner capsular membrane (ic). The outer 
capsular membrane (oc) is seen to take no part in the formation of the 
penetrating ridges. The stained nuclei of the capsular cells have not been 
presented in this figure, but the carmine-stained matter occupying the cavity 
between the ridges of the capsule is indicated by shading. This matter is 
the yelk of the egg, which is being increased by the addition of new material 
from the capsular cells. Actual section. 
Fig. 8. A much larger egg (in longitudinal section), showing the disposition of the 
ridges of the inner capsular membrane and the condition of the yelk-cavity. 
It is to be noticed that though the whole egg has increased greatly in bulk, 
the yelk-space has not as yet gained any thing as compared with the capsular 
folds or ridges. 
gv. Germinal vesicle. 
bv. Blood-vessels in section, lying between the outer and inner capsular 
membranes. 
oc. Outer capsular membrane. 
ic. Inner capsular membrane. 
c. Yelk-cavity. Actual section. 
