Central capsule lenticular, strongly flattened, about four times as broad as high, with a thin, simple-edged membrane. Nucleus lenticular, one-fourth as broad as the capsule, with numerous (twenty or more) small nucleoli. Protoplasm filled with dark pigment-granules; on the inside of the membrane in the circular periphery of the lens thirty-two dark oil-globules. Calymma lenticular, three times as broad as the capsule.
{ 16}_Dimensions._--Major axis of the capsule 0.2, minor 0.05; breadth of the nucleus 0.05, height 0.015; breadth of the calymma 0.6.
_Habitat._--Tropical Atlantic, Station 347, surface.
_Definition._--Central capsule lentelliptical, with three different axes.
Central capsule lentelliptical; with three different axes, bearing the proportion 4 : 3 : 2. Nucleus spherical; its diameter equal to the shortest radius of the capsule. No nucleoli visible. Protoplasm transparent, with small vacuoles; on the inside of the thin capsule-membrane numerous (fifty to sixty) small oil-globules, regularly disposed. Calymma lentelliptical, twice as large as the central capsule.
_Dimensions._--Major axis or length of the capsule 0.2, middle axis or breadth 0.15, minor axis or height 0.1; diameter of the nucleus 0.05, of the calymma 0.3-0.4.
_Habitat._--Central Pacific, Station 266, surface.
Genus 2. _Thalassolampe_,[9] Haeckel, 1862, Monogr. d. Radiol., p. 253.
_Definition._--#Thalassicollida# without extracapsular alveoles, but with large roundish or globular alveoles within the central capsule, with a simple spherical, not branched nucleus in the centre.
The genus _Thalassolampe_ is, next to _Actissa_, the most simple of all Radiolaria, but differs from it by the large intracapsular alveoles. By these the central capsule is inflated to an extraordinary size, which in _Thalassolampe maxima_ exceeds that of most other Radiolaria. From the nearly allied _Thalassopila_ it differs by the simple spherical nucleus, from _Physematium_ by the absence of spicula. Of the two species of the genus the first observed _Thalassolampe margarodes_, 1862, is Mediterranean, the second, _Thalassolampe maxima_, 1882, is Indian.
_Thalassolampe margarodes_, Haeckel, 1862, Monogr. d. Radiol., p. 253, Taf. ii. figs. 4, 5.