464 MR. H. N. MOSELEY ON THE STRUCTURE OF THE STYLASTERIDiE. 
flabellum. The ampullae are rounded cavities of irregular form, which, when mature, 
are so large as to he as wide as the side of a cyclo-system, and occupy it entirely 
(Plate 42). 
Numerous specimens of Cryptohelia pudica,, the soft parts of which are not pre- 
served, have several ampullae developed in connexion with each cyclo-system. These 
are concluded to be male examples. The ampullae are not nearly so large as in female 
specimens, and do not give evidence of their presence by forming swellings on the 
surface of the corallum. 
Soft Structures of Cryptohelia pudica. (Plate 42.) 
Coenosarc. — This differs in structure in no essential particulars from that of A stylus 
subviridis. Similar axial canal systems are present in the branches and similar 
surface networks, but these latter are finer and more complicated in the present form 
than in Astylus. The lid and its support consists of a reflection of the surface layer 
of ectoderm, beneath which is a prolongation of the surface network of the coenosarcal 
canals, and in the thicker portion of the stem of the lid run abundance of prolongations 
of the deeper and larger vessels (Plate 42, L). Rounded nematopliore sacs, closely 
similar to those of Astylus subviridis , are dotted about over the upper surface of the 
lid, and, as in Astylus, a single one of these bodies is jolaced at the margins of each 
cyclo-system over the outer extremity of each pseudoseptum (Plate 42, N, N). The 
pigmented endoderm cells are coloured brick-red as in Sporadopora dichotoma. 
Zooids. — The zooids of both kinds most closely resemble those of Astylus subviridis. 
Dactylozooids.— These are elongate-conical in form, tapering to a point. Their 
bases are attached as in Astylus subviridis. In retraction the part of them nearest 
the base is doubled back in the wide slit-like chamber of the dactylozooid towards the 
periphery of the cyclo-system, and then the remainder of the zooid is bent over in the 
reverse direction and doubled down into the mouth of the gastrozooid (Plate 42, D, Z). 
Gastrozooids. — These are flask-shaped and closely similar in structure to those of 
Astylus subviridis , being, like it, devoid of tentacles (Plate 44, fig. 1). The mouth 
appears at the flat summit of the neck of the flask as a cruciform aperture. The cavity 
of the zooid is lined with the usual gastric endodermal cells of elongate form, and the 
layer formed by these cells becomes, as in the gastrozooid of Sporadopora dichotoma, 
thinner as the base of the zooid cavity is approached. There is a thick investing 
ectoderm layer in the upper part of the zooid, between which and the endoderm layer 
is a well-marked layer of longitudinal muscular fibres, which fibres are, as in Spo- 
radopora, continued for insertion along the main canal offsets of the base of the zooid 
(Plate 42, M). 
The gastrozooid sac is attached just beneath the origin of the neck of its flask-shaped 
mass. The main canal offsets spring from the periphery of the rounded base of the 
zooid, with a radiating disposition (Plate 44, fig. 1). They curve upwards to be dis- 
tributed, as in Astylus subviridis. The calcareous wall of the upper chamber of the 
