MR, H. N. MOSELEY ON THE STRUCTURE OF THE STYLASTERIDiE. 4G1 
Gonophores . — Only one specimen of the present form was obtained and it was of 
the male sex. The male gonophores appear as large ronnded lobnlated masses 
resting within the ampular sacs, and springing from stout offsets of the coenosarcal 
mesh work, which pass into the sacs to reach them. Usually two tiers of ampullar 
sacs encircle each cyclo-system, being contained in the zone of ampullae described in 
the account of the corallum. 
The minute structure of the lobulated masses is shown in Plate 43, fig. 10. A 
membranous sac derived from the ectoderm and containing abundant nuclei in its 
tissue, S, lines the ampullar cavity and encloses the generative lobules. One or two 
large offsets of the canals of the coenosarcal mesh work penetrate this sac, and with the 
ends of these the central mass of the generative structures is continuous. This 
central mass is composed of spherical nucleated cells filled with granules, and closely 
similar in appearance to the endoderm cells which line the coenosarcal canals ; and 
apparently the endodermal lining cells of the canals, from which the mass springs, are 
continuous with those composing its substance. All over the surface of this central 
mass of cells, which is invested with a thin layer of ectoderm, small globose sacs arise 
as buds, and gradually increase in size until they assume the form of the ovoid 
masses, which, being thickly set over the surface of the central mass, and hiding it 
from view, give to the active generative mass the lobulated appearance figured in 
Plate 41, fig. 1, G. 
The young lobules when first formed appear as small rounded sacs with a thin wall 
of ectoderm, and containing a very few cells apparently derived from the main central 
mass. These cells become multiplied in number as the sac increases in size with 
progressive development. The sac as it enlarges becomes gradually pedicellate, and 
when mature is attached to the central mass by a narrow pedicle of some length. 
The walls of the pedicle are continuous with the ectodermal wall of the sac, which 
wall contains well-defined nuclei in its substance. Within the sac of the lobule a 
second sac, composed of a finer membrane, encloses the mature or developing genera- 
tive elements. The wall of this inner sac is not prolonged into the cavity of the 
pedicle, but passing across its commencement shuts off the main cavity of the lobule 
from this latter. 
The cells contained within the young lobule maintain a closely similar appearance 
to ordinary .pigmented endoderm cells, until they have become multiplied into a large 
mass. On further increase they change their structure and appear as spherical 
perfectly transparent masses, each of which contains a large nucleus which becomes 
most intensely stained when treated with carmine. These transparent nucleated 
cells, which are closely similar in appearance to those figured by Allman from the 
male gonophores of Laomedeci jlexuosa ,* multiply further by division, becoming very 
minute but retaining the same structure (Plate 43, fig. 10, C). 
From each of these minute cells a spermatozoon is developed. The head of the 
* Allman, “ Gymnoblastic or T nbularian Hydroids.” Ray Soc., 1871, paid 1, p. 65, fig. 316, 
