338 E. RAY LANKESTER. 
the very information they were intended to convey. It is for 
this reason that I am about to give a brief notice, accompanied 
by rough sketches, of a few points of interest in the develop- 
mental phenomena of the Cephalopoda which I ascertained 
during the spring of 1872, and subsequently during that of 
1874 at Naples. On the last occasion | had the advantage 
of making use of the arrangements carried out by my friend 
Anton Dohrn, in the Zoological Station and Aquarium now 
so well known. I have already given a very brief notice of 
the facts which I had observed in 1872,in the ‘ Proceedings 
of the Royal Society,’ 1874, and in the ‘ Annals and Mag. 
Nat. History,’ 1873. With regard to these two notices I 
have only to say here, that the statement contained in them 
to the effect that the primitive mouth aborts and a secondary 
mouth develops, is due to an error of interpretation. 
Where not otherwise indicated, the following remarks refer 
to Loligo. 
The Ovarian ovum.—I do not give here diagrams of any of 
my drawings illustrating this phase, since they will shortly 
be published in full. ‘The egg-capsule is at first composed 
of a single layer of cells, a second inner capsule or inner 
layer of cells then forms, which grows out in a series of folds 
into the space occupied by the egg-cell. From the cells 
forming the mucous-like epithelium of these folds albumi- 
nous matter is continually added to the egg, and at a certain 
stage of its development the cells themselves continually pro- 
liferate or bud off from the folds into the egg-mass. ‘The 
folds of the inner capsule are accompanied by blood-vessels, 
and it is their arrangement which gives the basket-work 
pattern to the surface of the ovarian eggs of Sepia, Loligo, 
and Octopus. ‘The outer capsule is smooth. ‘The inner 
capsule atrophies as its cells are absorbed into the ripening 
egg. Finally, the outer capsule bursts, allowing the egg 
to escape, leaving behind it a stalked calyx. 
The formation of the Blastoderm.—The egg on its escape 
from the calyx appears to have a very delicate pellicle or 
chorion on its surface, and there is a trace sometimes of the 
arrangement of the chief folds of the inner egg-capsule, which 
probably have a causal relation to the form subsequently taken 
by the chief cleavage segments. 'Vhe egg-shell which forms 
round the egg in the oviduct has a small hole at the narrower 
pole, which may be called a micropyle. Gelatinous material 
is subsequently added to this shell, embedding many eggs in 
the case of Loligo. I have not observed anything relative 
to the time of fertilisation. In Octopus the egg-shell is 
elongated and stalked (fig. 2). Within it may be seen the 
