320 M. Ussow’s Zoolugico-Embryological Investigations. 
To show the part taken by the different germ-lamelle in 
the formation of the various organs, I add the following 
Table :— 
The walls of the tube in which the os 
Sepie is formed, the epidermis (the 
outer skin of the whole body and 
the external covering of the funnel 
and branchiz), the organs of sight, 
hearing, and smell, the pericardium, 
all the cartilages (of the head, eye- 
lids, funnel, &e.). 
The upper lamella. 
The branchie, the arms with their 
The suckers, all the muscles, the cutis 
(fibrous layer, chromatophores, mus- 
dermo- cular fibres, &c.), the peritoneum, 
the branchial hearts, the kidneys, 
The muscular and all the blood-vessels, the organ 
of taste, the envelopes of the audi- 
middle layer. tory organs, the peripheral and cen- 
tral nervous system. 
lamella. 
The The walls of the central circulatory 
intestino- system, the auricles, the ventricles, 
fibrous the muscular envelope of the intes- 
layer. tinal tract and of the ink-bag. 
The intestino-glandular The inner epithelial envelope of the 
[ epithelial ] lamella intestinal tract and of all its sub- 
(the invaginated sidiary organs (cecum, liver), and 
upper lamella). of the salivary glands and ink-bag. 
Comparing the development of the three Decapoda investi- 
gated by me with that of the single Octopod to which I had 
access, I find a great agreement between them, but with the 
exception that the primitive groove which I have described 
in the case of the Decapoda does not close in Argonauta, 
In the time and the mode of appearance of the principal 
organs (alimentary apparatus, central nervous system, circu- 
latory organs, &c.) in the embryos of the two groups they 
perfectly correspond. 
The unimportant fact of the late appearance of the yelk- 
sac in Sepia, already remarked by Kélliker*, is the sole 
cree niitl of that genus that is not reproduced in the other 
Decapoda. 
* Luc. cit. p. 60. 
