6 
crumpled string without any nuclei and without a central canal. 
Thus the small medusa has closed its apical canal before it finally 
leaves the covering perisarc to live a free and independent life in 
the ocean. The furthest developed stages observed are undoubtedly 
very nearly ready for liberation; accordingly the medusa is liber- 
ated with 3 marginal tentacles, all very well developed. It is quite 
likely that a fourth or even a greater number of tentacles are 
developed later on. 
Development of the gonophore. — On the stolons in 
the same region, where the gonophores are placed, I found some 
short cylindrical bodies, the surface of which is densely provided 
with nematocysts. They are, however, covered by a thin chitinous 
perisarc, and these bodies have nothing whatever to do with de¬ 
fensive polyps or anything like that. They are simply the first 
developmental stages of gonophores. — Owing to the scarcity of 
material I am unable to give a detailed account of the development 
of the gonophores, but I shall give a short record of the stages, 
which I have observed. Apart from the first stages, the general 
plan of the development seems to be in accordance with that usu- 
ally found in medusoid gonophores of athecate hydroids. In its 
very first beginning the development is, however, very remark¬ 
able. It begins as an outgrowth from the stolon, this outgrowth 
developing into a cylindrical body several times longer than broad 
(PI. I, fig. 6). The outgrowth is, however, not hollow, but contains 
a solid endodermal core of large cells in a single row; the ecto- 
derm contains a large number of nematocysts, particularly in the 
distal part. The first trace of an interior differentiation of the 
body occurs near the base, where the endoderm cells begin to 
divide (textfig. 4), forming the first trace of a central space com- 
municating with the lumen of the stolon; externally this process 
is indicated by a slight swelling of the body. After the central 
lumen has been formed the development, probably, proceeds in a 
normal way. It is remarkable, however, that two of the tentacular 
bulbs (opposite each other) are developed and reach a consider- 
able size, while the interior parts of the gonophore are still at a 
low stage of development. Textfig. 5 exhibits an external view of 
a very young gonophore with two strongly developed tentacular 
