MR. H. N. MOSELEY ON THE STRUCTURE OF THE STYLASTERIDFE. 
491 
within the cavity of the zooid in the retracted condition of the latter. 
It is covered by a layer of ectoderm, and the endoderm lining layer of 
the zooid cavity is reflected over it. 
F, F. Walls of the sacs of the zooids. 
D Z. D Z. External openings of the sacs of two retracted dactylozooicls, one of which 
is very small, the other of the largest size occurring. 
B. Body cavity of the larger clactylozooid. In this zooid the ectoderm, E, is thrown 
into a series of folds in the retracted condition of the zooid. It presents 
on its outer surface a continuous layer of nematocysts. The zooid cavity 
is lined by a thick layer of endoderm. The zooid is attached to the side 
of the base of its containing sac, and is thus bent upon itself somewhat at 
its lower region. 
B. Retractor muscles, continuations on to the main basal canal of the zooid of the 
longitudinal muscular layer, which is seen in section in the upper portion 
of the zooid. 
N, N. Nematophores. 
D. Surface layer of the ectoderm. 
G, G'. Male gonophores. Those on the right seen in complete section, that on the 
left with its sac only opened, the generative masses being left intact. In 
G a ripe male sac filled with mature spermatozoa is seen situate nearest 
the surface of the coral, and beneath is an immature gonophore with its 
centrally placed spadix of endoderm. The axes of the two generative 
masses not lying in the same plane, the spadix is not seen in the upper 
riper sac, which is not divided by the section through the axis. 
X, X. Spaces between the branches of the coenosarcal network in the region imme- 
diately adjoining the sac of the zooid, where these branches have a 
peculiarly radiate arrangement, called here “ inter-radial spaces.” 
A, A. Slips of fine membrane attached to the radial offsets. 
PLATE 37. 
Section vertical to the surface of a portion of a decalcified female stock of Errina 
labiata, showing the form and dispositions of the zooids and gonophores. The meshes 
of the coenosarcal network are, as in Sporcidopora, closer and smaller in the more super- 
ficial than in the deeper regions of the coral. The zooids are all inclined towards the 
tip of the branch of the coral. 
D Z, D Z, D Z. Dactylozooicls. In two of these the sac or lining membrane of the 
pore is shown as cut open, in order to exhibit its relations to the contained 
and partly retracted zooid. 
D. A dactylozooid in process of development as a bud, 
