Observations on British Zoophytes. 
219 
pouch. This opening is closed by the ovarian membrane, 
which consists of three layers — 1. the endoderm, or intes- 
tinal layer ; 2. the gelatinous layer ; and 3. the ectoderm, 
or dermal layer. The ovarian membrane appears as a fioc- 
culent mass, from its being corrugated into numerous folds. 
By injecting air beneath it, it becomes inflated, and the folds 
are opened out. It then presents the appearance of a large 
transparent bag traversed by flat convoluted bands. These 
bands are the ovaries, and contain, between their endoderm 
and gelatinous layer, countless ova and planuloid larvae in 
various states of development. 
The ova of G. hyoscella do not present, at any stage, a 
trace of germinal vesicle or spot — objects which are so readily 
detected in the ova of other polypoid zoophytes. 
The planuloid larvae resemble those of Medusa aurita ; but 
the polyps into which they become developed approach more 
closely to the Lucernarian type, in having a pedicle which 
is surrounded by a gelatinous covering, and at its foot by a 
horny corallum, which I have described and figured else- 
where.* 
The structure and position of the male organs are remark- 
able. Attached to the inner surface of the ovarian mem- 
brane by deHcate pedicles, and projecting into the stomach, 
are numerous large grape-like bodies of translucent " jelly," 
accompanied in many cases by fringes of tentacles of the 
same substance (Plate IX. fig. 1), The surfaces of the firsfc 
bodies are dotted with minute papillae, and on the tentacles 
are found tubercles or thickenings covered with similar 
papillae. These papillae are sperm-sacs filled with sper- 
matic cells and spermatozoa (fig. 4). Smaller bodies, 
about the size of a hemp-seed, and specked with sperm- 
sacs, also occur attached to various parts of the lining 
membrane of the stomach, and even to that of the lips or 
long oral tentacles, doivn to the very tips of those organs. 
The small Chrysaoras (about 4 inches in diameter) have 
no ovarian bands in their pouches, which only contain masses 
of the grape-like bodies and tentacles before mentioned. 
These tentacles are not homologous with the minute, hol- 
* Edinburgh New Phil. Journal for 1859. 
VOL. IT. 2 F 
