REPORT ON CORALS—EXPLANATION OF PLATES. 217 
Z. Gastrozooid with twelve tentacles, disposed in a single whorl, and an almost hemi- 
spherical hypostome. Large canals spring from the base of the zooid, and 
form communications with the basal canals of adjacent zooid cyclo-systems. 
DZ’, DZ. Dactylozooids in their sheaths seen from behind within the adjacent 
zooid cyclo-systems. 
G, G, G. Gonophores. The sae of one of these is cut open to show the ovoid male 
generative masses and their spadices lying within. 
PLATE VII. 
Shows the structure of Stylaster densicaulis as seen in the decalcified condition. 
The cylindrical masses formed by three cyclo-systems of zooids are shown cut open, so 
as to demonstrate the arrangements of the zooids and ccenosarcal ramifications within 
them. The positions of the two additional cylco-systems are indicated by outline. 
In the centrally placed cyclo-system the entire ramifications of the ccenosareal canals 
are shown. 
In the system displayed on the left side of the figure, the wall of the sac of the 
gastrozooid, and the superficial network beneath it, are removed, in order to show 
the connections of the bases of the dactylozooids with the deeper canals. 
In the system shown on the right in the figure, the details of the connection of the 
base of the gastrozooid with the ccenosarcal canals only are given. 
The gonophores are seen through the superficial networks existing in the walls 
of the ampulla. 
Z, Z. Gastrozooids situate one at the base of each cyclo-system. 
DZ, DZ. Dactylozooids. GG. Male gonophores. 
N, N. Nematophores. 
A. Reflection of the surface layer of the ectoderm forming the sac of the gastrozooid and 
lining the gastropore. The sac-wall is very thin and transparent. Curved 
lines crossmg the dactylozooids transversely about their middles, in the 
central cyclo-system shown in the figure, mark the lower and innermost 
margins of the dactylozooid sacs, where these become continuous with the 
sac of the gastrozooid. In the cyclo-system shown on the left in the 
figure, the sac of the gastrozooid and the portions of the sacs of the 
dactylozooids fronting the gastropore are represented as removed, together 
with the superficial network of the ccenosarc immediately beneath them, 
in order to display the connections of the deeper systems of large main canals 
which connects the zooids of the cyclo-system directly with one another. 
B, B. Spaces in this deeper system of main canals. 
(ZOOL, CHALL, EXP.—PART ViI.—1880.) G 28 
