The central capsule with its nucleus; on the left side one valve of the closely enveloping shell (seen in vertical section), and its galea with the origin of the four tubes.
A complete specimen, with the central capsule and the enveloping phæodium. The surface of the spherical calymma is covered by a dense network, from which arise numerous, anchor-bearing, radial tubules.
A small piece of the superficial network of the skeleton, with the zigzag radial tubules arising from it, each of which bears an anchor with two recurved denticulate teeth on the distal end.
One valve of the shell (h) with its large galea and the origin of the three styles. The base of the two lateral styles (g1, g2) is connected by two latticed lateral frenula (b1, b2) with the mouth (m) of the rhinocanna (t). The odd style (g3) is free.
One valve of the shell (h), seen from the apical side; t, rhinocanna; m, its mouth; b1, b2, the two lateral frenula; g1, g2, the two paired styles; g3, the odd style.
The entire shell, enveloped by the yellowish calymma, seen from the left side; between the two valves is the central capsule, with nucleus and astropyle.
Dorsal view. The central capsule (red) exhibits above the anterior tubular main-opening (astropyle), and below the two small posterior lateral openings (right and left parapylæ).
Lateral view, from the right side. The two membranes of the central capsule are separated by a wide interval in this and the preceding figure. The nucleus contains numerous nucleoli.
Fig. 9a. Two of the peculiar cells, which are contained in the green phæodium in large numbers,
Lateral view, from the left side. In the oral part of the shell-cavity the dark phæodium, in the aboral part the central capsule with two nuclei (a dorsal and a ventral).
Lateral view, from the left side. In the anterior part of the shell-cavity the dark phæodium, in the posterior part the central capsule with the nucleus. The two valves are connected at the posterior hinge by a ligament (to the right in the figure).
Lateral view, from the right side. In the lower (posterior) half of the figure is visible the central capsule with its dark nucleus, in the upper (anterior) half the phæodium with two broad sagittal wings.
The two valves separated and seen obliquely, half from the lateral, half from the internal side. The inner opening of each valve is bordered and partly closed by a broad horizontal velum or diaphragm like the deck of a boat.
Fig. 3. Lateral view of the bivalved shell. The central capsule is visible between the two valves of the inner shell, the galeæ of which are filled by the phæodium,
One valve of the bivalved shell, seen from the inside, of the rarer polyhedral form, which may be distinguished as a different species (Cœloplegma tritonis, compare p. 1758). h, hemispherical inner valve; g, galea; s, its base.
h, The two hemispherical inner valves of the shell, seen from the right side; n, the central nucleus inside the central capsule; d, the astropyle; g, the galea; t, the nasal tube, arising from its base; m, its mouth; p, the phæodium, which is partly thrown out by the nasal openings, filling up the galea and nasal tube.
h, The two hemispherical inner valves of the shell and the enclosed central capsule, seen from the oral side; d, the radiate operculum of the astropyle, seen in the frontal fissure between the two valves; n, the nucleus; k, the crystals; g, galea; g1-g5, the styles arising from the galea; t, nasal tube; m, mouth of it.
Oral part of a central capsule, in profile. o, Opening of the proboscis; d, radiate operculum of the astropyle, which gives rise to the proboscis; e, the outer, i, the inner membrane of the capsule; k, groups of crystals; n, nucleus.
One inner valve of the shell, in profile. h, hemispherical valve; g, galea; g1-g5, the tubes arising from it; t, rhinocanna or nasal tube; m, its mouth; b, frenulum.
g, The galea; t, rhinocanna of one inner valve; m, its mouth; p, phæodella filling up both the galea and the mouth of the rhinocanna. g1-g5, the styles arising from the galea; s, sieve-plate, which separates the cavity of the galea from the hemispherical valve (h). View in profile.
Lateral view of the entire shell. The central capsule is visible between the two valves of the inner shell. The galeæ and rhinocannæ of the two inner valves are filled up by the black phæodium.
The two valves of the inner shell; the galeæ and rhinocannæ of which are filled up by the black phæodium. Between the mouth of the two rhinocannæ is prominent the proboscis of the astropyle, arising from the radiate operculum of the central capsule. The latter contains numerous crystals and a big dark nucleus. Lateral view.
The spherical central capsule is coloured red. The yellowish calymma envelops the radial spines completely. The polygonal network of lines, in which the radiating pseudopodia are symmetrically arranged, is partly visible.
Central capsule of a young specimen; in its upper half the peculiar kidney-shaped nucleus is visible, with its invagination; in the lower half some nucleated yellow cells are visible (intracapsular xanthellæ). These and the nucleus are stained by carmine.