MR. H. N. MOSELEY ON THE STRUCTURE OF THE STYLASTERID2E. 
409 
Fig. 10. Section through a portion of a male gonophore sac of Astylus subviridis, 
showing various stages in the development of spermatozoa [cf. Plate 41, G.) 
S. Wall of the gonophore sac, a reflection of the ectoderm. 
St Reflection of the same over one of the lobules of the generative mass. 
S". Thin membrane enclosing the spermatozoa within the lobule. 
E N. Endoderm cells. These apparently continuous with those forming 
the lining of the canals of the coenosarcal mesh work, X X, expand 
into a centrally-placed mass from which the lobules spring. The 
lobules as they approach maturity become attached by narrow 
pedicles . 
a. One of the earliest stages in the development of a lobule. 
b. More advanced stage showing a multiplication of the contained cells. 
c. Further stage with more numerous and smaller spermatogenous cells. 
d. Further stance. The character of the contained cells is changed. 
e. More advanced stage. 
f g. h. Further stages, h. h. Containing mature spermatozoa. 
Fig. 11. Successive stages in the development of the spermatozoa of Astylus 
subviridis. 
a. Ordinary endoderm cell. 
d. The opaque constituents of the cell are entirely condensed into the 
nucleus. 
e. Smaller similar cell produced by division of the above. 
e'.f g. Successive stages showing the development of the spermatozoon 
from the nucleus. 
Fig. 12. Ripe spermatozoa of Sporadopora dichotomci as seen in the living condition. 
A vesicle is present situate between the head and commencement of the 
filament of the spermatozoon. In the case of the lower spermatozoon of 
the three figured, the head, which is flattened, is viewed edge on. 
PLATE 44. 
Fig. 1. Gastrozooid of Crypt ohelia pudica, removed from its sac, and viewed directly 
from above so as to be much foreshortened in the drawing. 
A. The cruciform mouth, with a lining of elongate gastric cells. 
B. Main canals given off from the outer margin of the base of the zooid 
all round. These soon branch, and join by their offsets the general 
coenosarcal meshwork. 
The zooid is seen to be devoid of tentacles. 
Fig. 2. Part of a section, cut at right angles to the axis, of a cyclo-system of Astylus 
subviridis, showing the structures surrounding the pores of the dactyl o- 
zooids at the margin of the system. 
