1879.] 301 [Fewkes. 
type of development of either of the two mentioned above. It seems 
to resemble more the tentacular knob of a Calycophore, as a Gale- 
olaria or Diphyes, than the same structure in the Physophore. 
Between the polyps are curious organs of botryoidal appearance, 
which are commonly called the sexual organs. ‘They have never been 
found with any structure which can be likened to a germinative dot 
or vesicle, nor have the male been distinguished from the female ele- 
ments; indeed, they differ so greatly from sexual parts as generally 
met with among Siphonophorae, that one is almost in doubt whether 
they are really parts of this system or not. The-interior has a cili- 
ated surface, as Huxley pointed out. Situated on the stem between 
every pair of polyps, except those in close proximity to the float, we 
find from one to five of these clusters, wholly isolated from the re- 
maining parts of the animal. Like the other organs of the body, 
these parts develop also as simple buds, of two layers, in the form of 
a small bladder, smooth in outline and destitute of lasso cells. 
The first change in the growth is the formation of irregularities on 
the whole surface, as shown in fig. 14. These irregularities origin- 
ate in wart-like projections on the surface, and present an appear- 
ance whose outline is given in fig. 15. 
The structure resembles, as Gegenbaur says, a “ Morgenstern”, 
one of those mediaeval weapons in use before the introduction of 
fire-arms. The whole organ, in its histological structure, is composed 
of two layers: an outer layer, composed of transparent fibres with an 
intermixture of lasso cells; and an inner, sharply defined from the 
former, and clearer, destitute of cells, and apparently lined with cilia. 
I do not know certainly whether cilia exist, although both Huxley 
and Gegenbaur declare that the innermost surface, or the wall of the 
cavity, is ciliated. The different prominences of the botryoidal 
structure become more irregular in outline; the single elevations, in- 
stead of being spherical, take the irregular triangular form shown in 
fig. 17. That condition is followed by a specialization of growth at 
one angle, as shown in fig. 19. When the growth has proceeded 
still more, as in fig. 20, we notice near the apex of the prolonged 
portion a singularly large lasso cell, which remains constant in the 
more developed forms. Other adjoining cells of like nature make 
their appearance later, as seen in figs. 21, 22; the whole cluster is 
united, as seen in fig. 16. It sways to and fro independently, and 
can be contracted or expanded, as is the case with similar organs 
among other Siphonophores. 
i) 
if 
i 
pb 
t 
f 
i 
